We Prove Whether a Stock 426 HEMI Makes The 425 Horsepower That Chrysler Claimed Back in 1970
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- Опубліковано 1 гру 2023
- Back when we were building the "Comeback 'Cuda" for Mopar Connection Magazine, we took our nearly-factory stock 426 HEMI to Tommy's Auto Machine & Parts to see if this pachyderm really makes the 425 Horsepower that Ma' Mopar claimed back in the day. How did it do? Watch to find out HERE:
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#moparconnection #comebackcuda #426hemi - Авто та транспорт
MoPar rated the hemi as 425 HP @ 5000 rpm. What they neglected to say was that the dyno pulls went to 6000 rpm, and at 6000 revs, the engine put out 495 hp. There is a content provider on UA-cam, "Nick's Garage" and he has a weekly show specializing in MoPars. Particularly he works on a ;lot of 440s and hemis, although other engines come into the shop as well. In one of his shows he re-created a stock spec 426 hemi, totally stock except for a .030 overbore. He then ran it on his SuperFlow 902 dyno, and that's what it put out. Sure enough, at 5000 rpm it was 425 hp, but at 6000 the totally stock hemi put out 495 hp.
Ours began to lay over around 5750. You’ll see on the graph. We might’ve been able to duplicate his results with a bit more fuel and timing. Possibly.
@@moparconnection Were you running solid lifters or hydraulic lifters and if you were running solids were they set at .028 intake cold and .032 exhaust cold? Nick tightens the lash up on his until they "sound right"! The factory spec sheet the dealer gave me said .028 intake cold and .032 exhaust cold and .030 intake hot and .030 exhaust hot, didn't say a word about decibels, and they sure did clatter.
Almost up there with my 17' SS Camaro 6spd. rated at 455 net HP. SAE HP at the crank is a little over 500hp factory stock.
@@matrox Funny how many people get different hp figures on the dyno with the 426 hemi, most get 525hp at 6000rpm and power nation got 820hp with a blueprinted 426 hemi, who do you believe? I had a 426 hemi and never found any competition on the street and yeh there were plenty of muscle cars around and many were anything but stock and raced at the local strip and all top fuel dragsters and funny cars run Chrysler Hemis, just a fact of life. All I have to say is having power and knowing how to use it sure helps and spinning isn't winning, always left at 1800 rpm and never power shifted. And let's not forget that the 426 hemi and fords 429 hemi were required to run restrictor plates so the GM cars could keep up and that is another fact of life.
Compression would play a part. This had 9.6:1, Nick's was in the factory range. They say about 5% more power per point of compression. If this had 10.25:1 then that would add about 15 more HP, narrowing the gap a bit. Nicks may have been 10.5:1 but I could be wrong.
The 632hp 505 dual plane single quad Hemi he dynoed was what blew me away.
Beautiful Cuda. I'd rather have a tribute car than a museum piece you're terrified to drive and have fun with. Drive it like you stole it!
Amen!
Correct me if I’m wrong, but it’s my understanding that the 70-71 Hemis were hydraulic cammed. I love to see the difference of the 70s Hemi vs early models with solid lifters.
66-69 were solid/mechanical. 70-71 were hydraulic.
Nick's garage built one to stock specs too. It made 490tq/490hp.
Nice.
Lol. 😂
He was not running a water pump or an alternator, and his was closer if not at the advertised stock 10.25:1 compression ratio. The water pump and alternator parasitic drag plus the 3/4 point loss in compression will account for the 37 HP difference.
Hey thanks for the response on compression. I love watching the videos, have a great day. Thats crazy how the actual numbers would that off.
Yeah it’s super disappointing but given how expensive and frankly, difficult the Hemis were to machine, racers and builders found all sorts of inconsistencies.
Thanks for your approach to this Hemi build. The HP of these engines are all over the place. This is a good approach at what might have been delivered to the public in the 70’s. The Hemi is the most legendary engine offered in the 60’s and 70’ s and that is without a doubt. You either wanted a Hemi or you wanted to beat a Hemi. It was the litmus test on the street. Wether it lived up to the hype or not is not the answer. As legends go it got bigger and bigger in street lore. And as the top engine used in top fuel it also backed up the hype. Yes an LS6 454 is legendary too. As is the 427 Ford. Even small blocks have status. But the Hemi sits on top because of the hype. I have never owned a 2nd Gen. Hemi but I drove one one time in 79. A 66 Hemi Charger automatic. And I only got into it a little bit. But the torque was without question evident to me. If you wanted a Hemi to rule your streets, it took more money and wrenching. But it was an awesome starting package. Headers and a high lift cam would give back startlingly results. But tuning the distributor and carbs was a must after such modifications. The Hemi was a detuned race engine. And you had to return it back to what it needed to be with the right parts. You could go full bore and add 12:1 pistons and oil mods too. It was just what you could afford to do. Same with the other big blocks available at the time. It was definitely a different world in those days. And I miss them. Simpler times. Thanks for the video.
No this was meant to be a tribute to the car as it wouldve been in the showroom. I’m personally building a 572 Hemi that’ll be quite rowdy.
@@moparconnection I know. That is why I said your approach was as it would have been delivered in the 70’s stock factory car. Or my meaning was such. I bet that 572 is a beast. Now that is legendary.
I would argue it having the top "legendary status". I would say the ford cammer has more legendary status. What people's actual opinion is of the engine might vary. But as far as legendary? My vote would be the cammer. Becouse who dous anybody know that actually has or had a cammer?? In a rare moment one might see a hemi. But most never see a cammer in a liftime.
Yes I’m a Ford guy. I love the camera however it was never put in our car. Chrysler somehow offered from 66 to 71 like you say it was incredible time in history. I am 61 years old. I miss those days cruising Whittier Boulevard I graduated 81 back then you could buy a street hemi for around 04 to $5000 believe it or not. I remember gas being way under a dollar a gallon.😢
@stevo196two9 ur right, there is no Vin code that would indicate a factory cammer car. It was made available though as a "high rev, race ready, replacment engine" for your new Ford car. A over the counter ford replacment part.
Smooth job, guys! Mopar queen and the king of engines💪 Perfect!👌
We agree!
My wife has a real 71 Cuda, 340 4 speed, Bahama yellow. Needs a full resto, which is on my list, but for now it's protected
Whoowee! Gotta get on that project!
You guys aren't getting a divorce anytime soon are ya'?😊
Great video there Kevin love to see them all cars back on the road in excellent shape great horsepower and torque love the video
Glad you enjoyed it!
Awesome video. 👍 My Mopar is my 1968 Barracuda fastback powered by a 400 based 512 stroker featuring Trick Flow 240 heads and a hydraulic roller cam with 254 duration @.050 with 618 lift, backed by an A833 4 speed manual. 👍
Very cool!
Engine Masters tested the 426 Hemi vs a 440 and it turned out the hemi was great for….high sustained rpm but the 440 made killer torque for drag racing
Makes perfect sense
The difference in tq comes from the cubic inches not the top end. If a hemi had as many cubes it would have made just as much tq and way more hp.
@@DavidPhillips-rs5dq yeah and if a 318 was 800 cubes... it would make more power. BUt guess what.... it isn't Don't blame the OP because mopar never put any cubes behind the hemi heads.
@@DavidPhillips-rs5dqNo that’s not the reason. The Hemi heads are top end flow and suffer a bit down low. It could be a 440 Hemi and still make less torque than a 440
@@wyo_garage20 wrong
Joking aside, I do have just a bit of Machine shop experience under my belt, growing up in Flint, Michigan at Precision auto & Machine shop. I've never seen a pachyderm on the dyno that put out less than 435 h/p, most are up there around 450-480, Mopar really built a beast when they built that HEMI. Thanks for sharing this with all of us, I'm sure everyone else enjoyed it as much if not more than I did.
👍🏻
@@chadhaire1711put down the crack pipe Nancy 10% parasitic loss 450 gross is 405 net.
They all heavily underrated their engines. I have a theory that since they sold the cars all over the US. They needed to make sure even in say Denver the engines would put out their advertised HP.
Today our advertising laws are extremely lax. You can tell someone your polonium tea cures cancer and as long as no "reasonable person" would fall for your advertising. Well you can't be sued for false advertising. But our advertising laws weren't always like that.
It was for insurance purposes, less than 1 hp per CI, Ford 428 claimed 427hp Chevy 427 claimed 426hp.
@@chadhaire1711 it's 10% parasitic loss... 450 gross is 405 net.
Thanks for that awesome demonstration of the beloved hemi!🇺🇸
Glad you liked it!
My buddy who is working on my 70 442 is a huge mopar guy. He has some really cool cars trucks ect.. I think its a replica but 1 truck he has is The Little Red Wagon he takes it to Cordova for some show every year
Very cool!
I remember when Jim Drain from FL went out to see the 426 he had Dick Landy build, it made 525 HP and Jim was mad about it as it was going in his 1967 GTX Hemi 4 speed that was a pretty much an NOS car and the engine was supposed to be a stock rebuild. Dick just told Jim to calm down and when the Hemi was properly blueprinted, it would make these kind of numbers.
Dick knew what was up.
I'd guess Dick Landy was slightly knowledgeable on the engines
I traded a guy a boat for a '70 'Cuda w/ a 383 and one of the factory pistol-grip shifters, that I later found a Hemi for, along w/ one of the cross-ram intake systems Mopar developed specifically for these engines and high performance applications. What a screamer! With two Carter 850 CFM carbs it ran just over 10 second 1/4 miles. My favorite exercise was cruising at 3K-4K RPMs in second gear just to hear that engine sing. Back when I thought everything was replaceable, because I sold that jewel - its replaceable, right? smh
Holy cow! That's amazing!
The 426 hemi sold as a boat motor was rated at 550 horsepower
Yes and it had very different exhaust and cam profile
The mystique of the street hemi is the fact that it took mods better than any other platform, and yielding healthy results.
@@mindeloman The W125 was powered by a supercharged double overhead camshaft 5,663 cc (345.6 cu in) capacity 94 mm × 102 mm (3.70 in × 4.02 in) inline 8 which produced 595 horse power (444 kW) in race trim. Its highest test bed power measured was 637 BHP (646 PS) at 5,800 rpm, with 245 BHP (248 PS) developed at a mere 2,000 rpm.
@@mindeloman Mercedes had a smaller engine with more power over 30 years before. The hemi is a blatant rip off of the engine in the w125 Mercedes racing car. Americans actually made a worse engine and you guys think that it's better
@@beavis_loves_youlooking at the w125, it's an impressive engine. But how is the 426 ripping it off? Naturally aspirated and a V configuration I don't see the resemblance. Plus the Mercedes was a race only engine and ran on alcohol fuel mixture. There's really no comparison except for # of cylinders
Thanks for sharing great video
Thanks for watching!
Thx for truthful informative video...Your Dyno performance numbers seem just about right..With 1000 miles, my factory pure stock '70 hemi cuda Automatic click off 13.1's @ 107 all summer day long with full gas tank @ 4000 lbs.....Carbs never Touched, 4.10 Dana, 35° timing ....
Nice!
With stock tires?
@@kirkthejerkthe1stI seriously doubt that lol
@@midnight347 truly, why would you want a stock hemi?
Interesting.
I have a 426 in my '68 charger ( not original )
Its a late '66 casting.
The engine was built by Al Lee, of Lee brothers ( ' 68 hemi SS barracuda fame )
I talked to him after installing the engine and he told me he had punched it out 60 thousand and installed the correct factory mechanical cam.
Other than electronic ignition and a gorgeous 3" TTI exhaust, its totally stock right down to the Carter carbs.
Al told me, from his experience, it should be just a little over 500 at the flywheel.
This summer i plan on taking her down the 1/4 to see.
Awesome! That sounds like a lot of fun!
Nice to see some honest work giving honest numbers.
Appreciated!
@@chadhaire1711 Wouldn't that be rear wheel hp? That engine wasn't installed.
Nice video Kevin.
Would have been nice to seen some of the machine work and parts as well as the processes.
Should be a great engine.
Have a great day.
That’s why we linked the three dozen articles we wrote on it.
I have a 1969 Car Craft magazine issue in which they drag race test a 69 Roadrunner 440 6 pack automatic. They fiddled around with it and got some decent times out of it with slicks. As evening approached they realized the exhaust manifolds were glowing red hot after each pass and obviously a set of headers were needed. I've seen a true survivor Hemi Roadrunner that was absolutely bone stock but most people that bought a Hemi car for performance NEVER left it stock. A set of correctly made headers that match the stock cam and a correctly recurved factor distributor and the factory carbs rejeted by someone who knows what they are doing is worth 65 horsepower minimum so who gives a flip what the engine would do off the showroom floor ??
Precisely
People dont realize the StreetHemis were detuned race motors, which dont work real well on the street in daily use. A well tuned stock 440/6 will out run a Hemi half the time. We ran a 64 RaceHemi with aluminum heads and a Hilborn injector system in a steel 37 Willys coupe and it put out way more than 650hp on a basically stock motor (no wild cam or exotic stuff other than the injector and magneto)
Oh yeah, worse than that. Street Hemis weighed 812lbs, had lazy hydraulic camshafts and sloppy, misaligned valvetrain. Nothing about them were high performance.
I remember a magazine article back in the day where the author after driving a stock 426 Hemi car opined that he thought it was closer to 500 HP than it was to 425 HP.
We show it’s more powerful. Dyno results are real
Cool video,never seen a hemi before 84. But had worn out a few 440s,360s.
👍🏻
You mentioned this was rebuilt from a bear body. That would have been very difficult, because I rebuilt one from a hippopotamus body and that thing was a monster. So, hats off to you.
“Bare” is a very different word than “bear.”
@@moparconnection It was an attempt at a little humor on my part. Yeah, it wasn't that funny.
To be fair, we get a lot of comments from folks who otherwise wouldn't know the difference.
Thanks! Certainly no other engines could match the street hemi in 1966 when it came out and they would make more power in the upper rpm range than anything else.
Not the street ones, but with a little bit of love they screamed!
396 425hp and 7200 with ease in stock form
So it couldn't come within 50 hp of a hemi? That's nice
In 1967 Chevy responded with the "430 HP" L88 427" engine in the sales literature... that was actually 560 HP at 6600 RPMs...
The boss 429 was a monster. They were detuned for street cars and could make crazy power with minor tweaks.
Great numbers on the dyno , even with a fairly low compression ratio. Street Hemis were no slouch.
Most were dogs due to their weight (812lbs) and inconsistent machining.
Super cool video
Thanks!
Back in the day, insurance company's would not insure a car that had a greater than 1:1 hp/cid ratio. Hence 426 cid, 425 hp
Bingo
Back in those days there was high octane fuel at every gas station....You could run 12 to 1 motors with no issues...
That wasn’t because of octane but LEAD content.
@@moparconnection It was always rated in octane because of the higher tetraethyl lead content...Back then 110 was normal....And aviation fuel was 125/145 octane...
That will put a smile on your face
😁
I seem to recall the stock compression ratio on the OEM spec 426 HEMI was 10.25 to 1. I think yours is a bit low. That's a really nice engine, and represents the legend of the street HEMI quite well. Sounds healthy.
That was advertised yes, but records show that many of these came out of the factory with far less compression. Quality control was not the best.
Man I love engine rebuilds! Pontiac was the same way with sand bagging the power!
Most all were
one use to have i forgot was 70 or 71 Hemi Cuda back in 1971 and he used to race it a lot in Kuwait later it went to junkyard.
Oh my gosh!
How about a 2 or 3 part series on optimizing a Six Pack setup?
Not on this one, no.
A couple things.... wasn't the street hemi a hydraulic lifter engine?
Also, blue printed engine should make more power than an off-the-line one.
Where the hemi really excelles.... great lower rpm lift and stout bottom end - make for a really nice and reliable forced induction engine.
Yes all street Hemis were hydraulic flat tappets.
NO !! ....All 1966 (First yr hemi option) thru 1969 Street hemis came with Solid lifter flat tappet cam with only 1 slight cam upgrade during that 3 yr span....Hydraulic Only cam in '70--71 yrs....
That driver side front exhaust port looks like the manifold is strangling it compared to the others.
It’s what came from the factory
I understand, It's just a horrible design that was clearly the victim of packaging constraints.
Yep, switching from stock Hemi manifolds to headers was worth .3 all by itself for me at Muncie Dragway.
Back in the day the 426 was no joke especially when you had high performance 3 duce 4 speed the I was around in 75 had never been rebuilt and turned 6000 rpm with no complaints.
No such thing as a triple deuce Hemi from the factory. Only dual quads.
I never knew that the #1 cylinder exhaust manifold was so restricted.
Factory stock wasn't very forgiving to these engines.
I can confirm this is an early factory HEMI solid lifter cam (or repro) as I measured the lobe lift in my lathe and it was right on spec.
Thank you!
When you say early, does that mean the mild series 1 solid cam used in 66-67, or the bit wilder series 2 solid cam used in 68-69.
Most likely 68-69 based on specs. I meant early as its a solid cam and not the Hyd correct for 1970. @@jamesblair9614
Good video
Thank you!
In 1970 Hemis came with a hydraulic cam I believe, so no E body solid lifter cams.
I’d love to see documentation for that because we couldn’t find it elsewhere.
This doesn't sound right, but according to my vintage Motors Manual (early model edition 1968-1974), only the 1971 426 came with hydraulic lifters. All other 426's were solid lifters clearanced at .028 intake and .032 exhaust (cold). The hydraulic cammed cars had adjustable rockers and a spec. for that.
The 70-71 Hemi’s all had hydraulic cams, the specs were the same as the 68-69 series 2 cam, just hydraulic, and they still retained the adjustable rockers, but shorter push rods. Just look in any 70-71 service manual for documentation.
Just as I originally stated. My Motors Manual must be wrong!
@@moparconnection He's correct, hydraulic lifters for Hemis starting in 1970. It's called out in the '1970 Challenger Lineup' dealer binder, and again in the 1970 Plymouth Rapid Transit System advertisement, page 15. I'm sure it is also called out in the factory service manuals, but I don't have a '70 on hand. No solid lifter E-bodies.
Mopar Connection Magazine....In fact, the only way to build a ''numbers matching motor'' for this car was to rebuild the 318 original motor...That is the only way...any other motor won't match...unless you punch new numbers on the replacement motor that you stick in it...
At the most anal of definitions, yes you are correct. We mean replicating a DATE-correct build.
Sweet 💪
Very!
Probably more like 465-475 with 10.25 compression like factory. Great job.
No the compression is still under 10:1.
I'm really surprised it wasn't more, although I'm not a Mopar fan, the big 3 underrated the horsepower back then to help squeeze thru insurance prices, yes the insurance company's were eating people alive on the high horsepower cars back then too
We all believe this claim that they all “sand bagged” but it isn’t necessarily true
Good video, and fun to see numbers. Why though run not factory compression? If the goal was to show what it could do? I don't know how much you lost but would be some for sure.
We did. Factory crank, rods and pistons with the identical compression height. The factory was famously inconsistent and this was one example.
Had a 1967 Satellite with the 426 Hemi 4 speed dana 60 with 3.54 gears with a track lock. I believe the compression was 10.25:1 with a slightly smaller cam then the 68&69 Hemi's. First thing I had to do was adjust the valve lash, .028 intake and .032 exhaust cold, oh my did those lifters clatter, everyone who got in the car told me there was something wrong with the engine. I know for a fact that many dealers would set them at zero lash because people would not buy them for that reason. I made two changes to the engine, one; a set of chrome moly pushrods and two; added a braided copper wire between the stationary plate and the breaker plate to eliminate ignition breakup from 5500rpm to 7000rpm. And for whatever it is worth yes it would turn 7000rpm in every gear and no you didn't hold it there in any gear so as not to grenade it and you didn't power shift it into any gear unless you wanted to do a donut. It was on H70/14 Dunlap bias ply tires so there wasn't a lot of rubber on the road. Don't understand why people complain about the Hemi being a dog on the street unless they just didn't know how to drive it. And I have talked to a few former Hemi owners and no they didn't. And hey even Nick from Nick's garage tells me he reduces the valve lash until it sounds right to him!!!!!! Gee I wonder if that's why they had a reputation for valve train wear, DUH!
That’s an awesome story! Man, that sounded like an awesome car.
Yea it was and I still miss it. I have a 66 Satellite and a ton of 440's, 400's, 383's, 360's, 340's,318's, but no Hemi. Now if I could just be lucky enough to hit the lottery! I am guessing you know enough to run a remote oil filter and pipe one return into the passenger's side at the rear of the block where the sending unit goes, this will prevent oil starvation on 6,7&8 rod bearings at high rpm and you know to keep your engine loaded, pulling, when winding it so as not to blow it. No better way to blow an engine than to wind an engine with no load on it, another reason why I never power shifted.@@moparconnection
That's odd. My 70 340 6bbl, had a similar distributor, Prestolite dual point, and it came oem with a braided copper ground wire.
Don't know what to tell you, but the distributor in my 67 did not have one until I installed one, maybe someone at the factory figured out the same thing I did and yours was a 70 and mine was a 67 and as we all know the factories were always making changes. You're making a big assumption that because your 1970 distributor had one that my 1967 distributor had one.@@budlanctot3060
@@stephenwest798The Hemi will also have piston slap noise when cold too. Did you do the lash the same way us HyperPak Slant blokes do? - While It's Running 😊 Gets perfect lash at operational temperatures, solid cam and lifters (like the 273's had in the 60's) on the stock Slant always sounds like a sewing machine running somewhere under the hood. But once it's right, throttle response is crisp, and the emissions go way down, same with fuel usage out on the freeway. The valve train with correct lash and replacing the stock phenolic cam gear and morse chain with a roller chain and gears on the Slants and the V8's, the valve timing stays perfect, the ignition timing stays perfect, the wear goes away to the point you can run the Lean Burn computer and have it be reliable. Check the lash every couple of filter changes, these things just keep going.
Another thing the big 3 did, was to leave off things like alternator, water pump and mufflers or anything that would sap horsepower. We have to mention also, that the horsepower rating system went from gross horsepower to S.A.E. net horsepower in 1972. This meant a certain standard was adhered to, like mufflers, water pump and the room at 70° Fahrenheit. The year prior (1971) saw the first round of emissions phased in. While none of this affected a 1970 engine, we no longer live in the year 1970 and horsepower today is measured in S.A.E. net. I find it amusing that gross horsepower is still used in some areas, like rating lawn mowers or farm equipment.
They ran water pumps in the dyno
i think back in the day they did typically underrated the HP , for insurance purposes. It really was weird how just a few HP lower could save you money on insurance. But Ive seen 500 hp on a pretty much stock dinosaur Hemi on cheap pump gas. though i wouldnt recommend doing that daily driving. Lol
This was an almost perfect stock example and made a little over 450.
So, 438 CID, but compression a full point lower than the Street Hemi. Those deviations may offset and get you close, but I'd still like to see what real factory-spec hemis made. I suspect that will keep getting harder to find as years go by.
Not quite. While Chrysler advertised 10.25:1 many engine builders found their street Hemis had far below that compression ratio. The compression height of our pistons, rod length and crank all remained identical to stock. The block wasn’t decked and we compensated for the decked heads with a thicker gasket. It came out to 9.6:1.
450/480 sounds more like reality. Too many guys saying they made sooo much more like 100,
lol. That torque curve kicks butt for any st car. So many focus on a hp number but totally ignore the tq which is where it makes the beans.
Torque is where it’s at!
If i remember right that's why they called it a 426 hemi . it was the one you wanted in your car on the first date or going shopping on your last ones at 70 🙂
👌
I did in summer '70.....Kinda cramped at Drive-ins but we managed !!!
That was a great video. Your approach was to see if the numbers were realistic and repeatable if everything was left stock, which you have proven to be true. Yes you could have tweeked this etc like so many have done to get maximum #'s, but that wasn't the way you built the engine, so why would you push the new engine beyond what it was meant to do? What I would like to see is follow up stories as the miles get racked up, to see if the reliability is there. So many of the engines were destroyed from drag racing you never saw a 100k mile unmolested survivor still in the origional car for one reason or another. So I assume this car will be driven for all the time and money spent to get it on the road so keep us in the loop please .
Solid suggestion but the owner of the car didn’t build this to be a driver (sadly). When I build my 572 Hemi then you’ll see us rack us some miles!
What an absolute legend the Hemi is. But no, not just a legend; the beast really delivered.
Absolutely. Not a legend but raw reality. Tons of power in that block of iron.
👆🏻
Chrysler was a group that had engineer's who wanted creat vehicles that were the best and executives who wanted to succeed as a buisness and bean counters who only cared about the bottom line and managers stuck in the middle. So they were not the first into racing, it took employees on their own time and money racing for the big wigs to see winning on Sunday sells on Monday for them to green light certain projects.
Once they got involved in something they were not going to be shown up, so they dove in head first. What they lacked was the follow thru and appropriate time to allow this projects to get off the ground and flourish. Examples are the Winged B bodies for NASCAR and the TA's and AAR E bodies both made in short runs , Daytonas and Superbirds and 340 6 pak challengers and cudas 1 model year each. Even the Hurst Hemi A bodies were one model year as well but those were not built for the street but the same thought process is still there.
Its like see what we can do ......
Next short term project please....
Maybe they had ADD before we knew what that was????
👍🏻
The 1970-71 Street Hemi had a hydraulic cam with same timing specs as the 69 solid cam...so they say. You could not find a correct hydraulic cam? My brother still has his 1970 Hemicuda he ordered new. I have the original factory hyd. cam which had 10,000 miles on it. I set it up in my lathe and like you checked out the numbers. I got 228 degrees duration at .050 and a gross of 284. Lobe lifts at .309 to .311 I made a dummy lifter of the correct diameter of a stock Hemi lifter and dial indicator off of that.
Find a major camshaft manufacturer that reproduces the original cams. We had to have COMP grind one close to stock.
It probably picked up the few extra horsepower due to the better fuel we have today and also the engine dyno Dyno technology is way better than what they had back in the '70s and way more accurate over the analog that we had back then. So you can think of how many engines that we're probably underrated for their time back in the day.
👍🏻
That's fine, just box it up and I'll be there about 9am tomorrow to load it up. lol.
😆
Good thing you used an earlier solid lifter version. The 70 - 71 used hydraulics and wasn't quite the same.
We couldn’t get one made for us
@@moparconnection If you mean that you couldn't get a hydraulic one made for you, that's a good thing, unless you enter it into a Concours De Elegance, where they would deduct points for not having the correct year engine.
9.6:1 compression ratio? Street HEMIs were rated at 10.25:1, were they not? The .060 overbore skews results as well. Great effort, though. I think we can all agree that the Elephant, like most engines of the time, was underrated. Thanks, fellers!
What was advertised wasn't always what engine builders found to be true in 1970. The machining on original Hemis were atrocious at times; some even found true compression ratios to be under 9:1. The overbore doesn't effect much when we measure the quench to the exact same 75cc as factory stock.
The hi po engines back then always put out more power. They lowered the numbers for insurance purposes. Great build.
Some did, yes. Others manipulated how HP was calculated/
That's true
Lol, no.
Lower numbers also mean that one customer that hates everybody couldn't sue over finding out it had less power or torque then claimed.
Americans were far less litigious pansies back then.
Okay I’ve read all the comments. I can’t believe that nobody even mentions the A990 despite the fact that it was a production motor available for a while in anything chiseler made that was available with a big block. I’ve seen an Imperial with a factory A990.
A990 was NOT the engine. It was the code ascribed to the car.
"Imperial A990" that's funny !!!
I think that with some better tolerances today and machining skills it helps get a few more hp out of the "factory" motors. The race motors of the time had this 'extra' work and time put into them. But I don't believe for a second that the "street" engines in the factory cars were as under rated as the internet seems to believe. Like the rumors that the L-88 corvette 427 was really a 600 hp engine but ONLY rated at 435 in the car. Maybe 25 hp at most.
The race Hemis were absolutely a different animal than the heavy, slow revving street Hemis.
The L88 427 was rated at 430 HP to get it under the top normal street 435 HP 427 so unknowledgeable rich kids wouldn't order it... stock L88s dyno at 560 HP @ 6600 RPM with headers... L88s were in the Corvette sales literature... even available with automatic tranny...
Aluminum heads L89 or all aluminum ZL-1 427 more like 530 HP as aluminum bleeds off heat/HP faster... but saves weight...
I have nothing against clones/tributes. There are only so many factory big block super sports/rt’s/cobras in the world.
Bingo!
You can pull a spark plug wire off and make a 425 hp pull with a 426.
That’s the rumor but that was with a ‘66.
Seems to know what he's talking about I'm in. My favorite hemi is the 331.
Nice!
Back in the 60's and early 70's those hemi engines were designed to run on pure 100 octane gas with no ethanol or emissions additives. Low 90 / 93 octane was considered regular back then. Not bad considering we have inferior gas nowadays compared to back then.
Leaded gas made the biggest difference
@@moparconnection Absolutely. Leaded gasoline although bad for the environment, was great for engines without hardened valve seats and catalytic converters. Pure gas is not watered down with a percentage of alcohol or alcohol cosolvents / MTBE etc. Leaded gasoline falls into the "pure" description because it too wasn't watered down.
The octane rating back then was the research octane. Now it is the average of the research and motor octane, and motor is about 10 points lower than research. 100 octane gas in 1970 is equivalent to about 95 octane now, so higher than the 91-93 that you can typically get at the pump today, but not as much higher as you might have thought.
Ethanol adds hp generally as it is carrying extra oxygen into the mixture... sort of like adding a small shot of nitrous
Yeah and a 98 camaro could outrun a stock hemi from the 60s on that fuel so
Remember that is a street Hemi. I'm guessing the race Hemi had more like 600hp
Absolutely- if not more!
I owned one of the few Hemi Road runners 1970, this car was a brute and was denied at Ramchargers at 495 hp at 6000rpm, I loved it but was sold as kids came and sadly totaled 2 months later
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Not likely.....Except on "Happy" dynos, No Factory street hemi made nearly 500 Hp..The very different (Big cam,12.5 CR, Tuned X--Ram intake + Bigger Holley carbs) factory built Race hemi was Typically in the Honest 550--575 Hp range....
Chrysler has ALWAYS understated the numbers on Every(!) engine that left the factory. There's two reasons for this, first is MoPar engineers like to go fast. Second is, no one, ever, can sue them for false advertising on the engine power.
Doesn't matter if it was a baby Slant, Minivan V6, Neon 4 or fire breathing Hemi V8, they ALL had more power and torque then the stat sheet claims.
Hmm... it wasn't due to people being litigious in the 1960s and 70s but insurance companies and the federal government.
@@moparconnection "No one",... includes Da Gubermint,... ;)
( Smiles in Slant Six HyperPak VC Valiant )
From all the Dyno videos and posted Dyno tests posted online not all Hemis are created equal. But everyone made the rate 425 hp(=-) @ 5000 rpm. Yes Chrysler sand bagged. Most make at least close to 450(=-) @ 5500. Hemi like to be tuned to make power. There not a slap together engine like the other big block from another manufacturer. That’s why people build the other big block from brand C. You can slap them together and get more power.
Not necessarily more power but certainly CHEAPER.
You can see clearly from the chart that after 5500 rpm, the power dropped off. That means that in this configuration, this engine made 452. 7 hp tops. It is only turning a water pump and an alternator with an open headers exhaust, which means that this is basically gross horsepower. Modern Ford Mustang 5.0 liter/302 cubic inch DOHC 32 valve engines make 480 hp at the crank but that is NET horsepower.
These old engines are fascinating, but they aren't what people think they are; Modern Hemi's would use one of these "elephants" as a breakfast food....
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Nobody knows how to get hp out of a hemi than Nick! he's the best!
He’s brilliant
Uh, I would not discount Ray Barton!
Should've sleeved it so it really was the factory displacement and restored the cylinder strength.
It had crossed our mind but would’ve doubled the cost of the machining.
Would have been far better off pulling out useless mass with modern pistons and rods, and not having to further sodomize the crankshaft welding mass back into it. Could have really been money ahead going to 2.200 BBC rods on the crank throws. But I get that it's fun to see what the old junk would do "back when" and it's a cool car, with a resto build engine.
“Sodomize the crankshaft” - bro, calm down.
@@moparconnection 🤣🤣
That car is gorgeus , a Cuda in violet 🍻 , that 70 year , the cuda , the road runner the best of plymouth .
Yeah we’re pretty proud of it
Elephant Power!
Yessir!
The std Available factory options should've Included something similar to the "Max Wedge" X-ram intake Holleys & properly Cam'd & High domed factory Race version....550hp flywheel Easy.... Would've been a Total game changer Max perf street car....but they Didn't.....
There were plenty of options through Direct Connection to hop up the engine once it left the dealership.
There was no "Direct Connection" dealer Participating support during '66 thru '71 available until 1974 ....No Factory/dealer help at all for Original Street owners & Typical Chrysler dealers had No knowledge or showroom Brochures on the very rare limited Production, race Only drag package car componets so You were on your Own in middle of "Nowhere USA" & No dealer support.....Unlike the extreme limited production, Factory S/S race car package Hemi with Deep plunge cut valve Relief pistons, All street hemi engines came with Extremely tight valve relief low compression pistons requiring Extreme piston--valve clearance checks/Machining to safely accommodate any longer Duration, higher Lift camshafts or you Easily Bent something extremely Expensive during your "On your Own experimental" cam swap job start up !!
Chrysler rating also had a astrix that in fine print said rated for insurance reasons
Where are you seeing this?
Hardly....They (Mopar dyno engineers) Configured it for 425 Sae Flywheel hp & went Out for lunch (Engine still on dyno throttle to 425 hp) returned still seeing 425 hp.....That's Why they rated it at an honest 425 hp.....Street hemi Wasn't their Prime concern as they (Chrysler Race Division) Needed to sell a few hundred per yr to make hemi Legal for Nascar track & Nhra drags.....Street hemi was simply Deballed for 1 yr/50k mile Warranty with most all other engines at their 5 yr/50k mile warranty.....
1 yr/10k mile actually !!
🏆The elephant🏆🍀King Kong👀✌️
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Factory Hemi compression in 1970 was 10.25:1. You're leaving power on the table.
Please read where we answered this like 12 times before
Those engines were designed to run on 101+ leaded octane fuel.
Find me documentation because I’ve never seen that in my 21 years in this industry
@@moparconnection There is no documentation. The Hi-test fuels back then at the pump were 101+ Octane rated and contained lead. Performance cars were designed for Hi-Test.
@@matrox most 3rd party media testing was done with 90/91/93 octane (Motor Trend, Hot Rod, Super Stock, etc.). Rarely did you ever see factory dyno results using 100+ octane - albeit all of these were will leaded, zero ethanol fuels.
@@moparconnection I'm not sure what year you are from. Back in the day 60s and early 70s as remember the fuels were leaded from low 90s octane as regular, hi 90s as mid grade then super/hi-test from around 101-104 octane.
@@matrox I'm 74 years old and I don't remember any 101 octane pump gas. I think Sonoco had the highest rating @ 100 octane. Most other stations had 97 octane. All of it was leaded back then.
Interesting how all these old engines make 50-75hp more than they did when originally tested.
It’s a mystery!
Better oil now, better machining, better rings...
@@JeffKopis I agree to a point. I’d say there is some exaggeration going on too.
I SEEMED TO HEAR A VERY LOUD TICKING, VALVES ? AFTER THE PULL. DID I HEAR CORRECTLY?
Admittedly the audio equipment I used wasn’t very good. It picked up a lot of noise that was distorted. The Hemi ran great.
I believe the factory street hemi had 10.5 to 1 compression to....
Advertised, yes. Actually? It was often VERY irregular. Sadly, Chrysler's finish machining on these blocks and heads would sway radically. That's why every good street racer took their apart and remachined them to exact tolerances.
Back when these V8's from all big three got about 10 years old, bunches sucked valves from worn out valve springs above 5000rpm. I could buy $50 long blocks for parts from all Detroits big 3.
Sadly yes
Chrysler's Hemi was a great race motor, with a wide power band. But that didn't always translate to street performance. A good 440 was usually better and many a hemi car wasted away in the garage after a few thousand miles because they needed constant, competent tuning to maintain optimal running.
Street Hemis really weren't much mightier than any other big displacement big block; in fact, most stories shared of high revving small blocks besting a street elephant have plenty of credibility.
@@moparconnectionTrue. They usually had a weight advantage also. Back in the sixties a big block Chevy could be built to put out more peak horsepower, but the Hemi's strength was it's very broad power range, lots of torque and endurance. Although in the F.A.S.T. series, a lot of Buicks bested the Hemi cars.
The factory ratings were gross hp, no water pump, no air cleaner, fan, alternator, ps pump or full exhaust system. You’re running a water pump but also a .060 overbore so probably balances out. Cars today are rated on a net basis with all accessories in place and the full exhaust system. Be interesting to see a true net run on one of these to see how they compare to modern engines.
This is patently false. On literally every level.
@@chadhaire1711 no Chad, I'm talking about ridiculous claims that Chrysler didn't run water pumps, etc. They had to run the engines "dressed" by FEDERAL LAW, not to mention that I've personally interviewed Tom Hoover (years ago). They ran the engines as-is from the line.
How is a 9.6 compression the right number you were looking for? The street Hemi had 10.25 compression. As far as horsepower numbers go none of the big three were telling what the true horsepower numbers were as they always picked a lower than peak RPM numbers to give the insurance companies what they wanted power wise.
We’ve answered this thoroughly in other comments.
Not quite.....Most '66--'71 Street hemi engines were Factory built with significantly Larger (173 vrs 170cc advertised specs) cyl heads + significantly Taller block Deck height putting that 10:25 CR spec piston way Down the hole resulting in much Lower ("Bout 9:1) CR....Original owners never Knew unless someone tore down & Measured your engine.....
That is a very low compression motor without a big cam and still made more than 1hp/in. Just give it a little more cam and 11/1 compression and then it should wake up more. I think you could run this motor on the street on regular gas. that is why I built a 9/1 Chevy 350 for my 69 Chevy van. I run regular gas with a larger cam than this motor is running. Or put some 1.7/1 rockers on the intake.
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Everyone know that most of these engines had more power than advertised.
BUT you have fitted it ro a tent car,, they flex badly. Then fitted with the tyres that killed hundreds,, Badday Polyglass. So you have a 140mph car with a 70mph chassis on 20mph tyres.
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Best part was these were somebody's daily drivers!!!!!😅😅😅😅😅😅😅
Amen to that!
Nick Panaritis of Nick's Garage (www.youtube.com/@NicksGarage/videos) Dyno-tested a BONE-STOCK 426 Hemi set to Factory specs and it pushed out 490+ hp....
ua-cam.com/video/QB7Iug0ILAY/v-deo.htmlsi=oUT7CXzLf_0m9KqO
Nice!
With a hot cam and good compression 600hp wouldn't be an issue.
Agreed
What was your timing?
As I recall we were at 20 initial and 38 all in.
Wasn't the stock Street Hemi set up at 10.25:1 compression? Sounds like that head gasket may have been a little thicker than necessary.
Please see the other times we address this in other comments.
Pretty sure all the manufacturers played with the HP numbers during the musclecar era, both to sell cars and keep themselves out of the doghouse with insurance companies
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I've never heard anyone say that hemi power was over rated
Nor did we