Oval Port Heads VS Rectangle Port Heads Promaxx 290 vs Promaxx 317
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- Опубліковано 9 лют 2025
- I give dyno comparisons between a set of Promaxx 290 oval (roval port) heads vs Promaxx 317 heads. I show flow numbers and dyno numbers.
You can contact me at weingartnerracing@gmail.com
or my website wengines.com
Loving this series, incredibly great info
For the street....not quite big enough is often better than a little too big. Same goes for camshafts....but man is it hard to try to get people to go smaller because everyone wants that lumpy race cam sound. Great testing as always Eric....well done!
I dont even care about that, I look for gains in Torque under NA conditions.
@@shadowopsairman1583 me too! On a street engine I want a torque monster.
My street cam has duration numbers of 224 and 234. Tiny compared to what most are running. But, I don't need power and torque way up in the rpm band. Especially with a heavy car.
Mine still has plenty of lump too
@@shadowopsairman1583 with these 290s id even run something like a crower 01245 if i was flat tappet (6500 RPM redline in a 454-468) or a roller equivalent. with an airgap and an 950 street Q
easy 600 right there
Takes a little while to figure that out..Hee hee.
I like the BBC testing Eric. I know it's a lot of work and it's much appreciated. I have both SBC and BBC builds here but enjoy making HP with BBC's. For the record I go with the bigger heads every time on my street/strip cars and currently run the AFR 305's on a 454. There is no drivability issues down low, in fact it'll make more torque than most can handle in their street cars anyway and a properly setup car with the right converter will blow right past those low rpm points at WOT making it a non issue. Part throttle drivability is still fantastic. Looking forward to seeing more.
Thanks for the videos I see almost every one and share them with my friends and family. I’m not currently building anything but when I I get started I will be supporting by getting parts through you.
I started watching because of your brodix bb2 plus review. I should have watched all these videos before I had purchased them! Great info
I have run 180 - 200 pounds on the seat and 480+ pounds open on a big block Chevy to avoid valve float with a hydraulic roller. The high rocker ratio and heavy intake valve are hard to control, even with 11/32 stems.
Ti retainers help on the BBC
@@donavan2676 Ti retainers get another 300 rpm or so. Which might be just enough to make them worthwhile. But I have still not found a better combo than a good double spring for a hydraulic roller big block Chevy.
I wonder if a large beehive spring like PAC 1295X would help it rpm. I think it would be worth it to do a test.
@@ekitching Sure, it would probably be better at rpm. It's also over $400 my cost for those, with retainers. I often find myself in a position where the customer can't or won't stretch the budget for those springs and also a good set of lifters, like a Morel 5045. Since the Morel lifters can take the pressure from a good dual spring that's usually where I land.
@@ekitching We use the 1255X in these heads with light weight retainers and get 6800 rpm reliably with short travel Comp lifters.
On the FloTek, and Pro Maxx heads there is some easy power to be gained by blending the seat better into the combustion chamber, and a bowl blend
Another great video Eric keep up the great information GODSPEED
Great video Eric. My vote is mill the 317, gasket match the 454-0, re dyno. thanks a ton.
When and what will be the subject of the next book? I’ve really enjoyed all of the previous books, and I’m looking forward to the next one! Thanks a million for your vids. They are educational as well as entertaining! Again, thanks a million!!
Love and oval port . Have you people never heard of D- porting a head. That’s how I learned to absolutely make tons of power with a oval port head from a great engine builder in the 80s his name was Ottis Cambell from Lacey’s Spring Alabama
Thank you for sharing this with us IT is very much appreciated Look for this name on 11/21-11/22
I have always been curious why chevy moved the port down on the peanut port head instead of filling the bottom of it and moving it up for a better shot at the valve? Also have you ever experimented with different clay radius when flowing heads? Is there a difference from say a 1/8 inch radius up to 1/2 inch radius or even just variations of how well it is shaped by hand?
I yeah I don’t know a whole hell of a lot about a dyno machine, but I have watched a Lotta videos on them and as far as I understood if your machine is calibrated perfectly and then corrected for weather, you should be able to run them on two different machines and get within close numbers that’s what I’ve always understood
Since were talking about dyno's accuracy from dyno to dyno at least in my opinion I think its important to mention this 290 headed engine is making 581 HP before the correction is applied at 1260 feet altitude. I've seriously thought about just rating my engines HP from observed or measured HP in the past, but that can be inaccurate as well if the dyno is out of calibration.
I would ask you to hold these comments until you test there.
@@WeingartnerRacing If I'am wrong about the observed HP @ 6100 RPM on the 290 test engine please correct me. The data was hard to read, but I think I have it right @ 6100 RPM.
I'd like to see a complete test of a true oval port aluminum head for a street engine. 468 cubic inches or less preferably. Roller cam, N/A with a 150 shot maybe?
This (or there abouts) is the setup a lot of guys are running. Street and strip.
But the 317 isn't available in a 2.25 valve head. I wanted to run the 317 but they discontinued the smaller valve head. So now I am stuck with my wiseco pistons that are a street strip piston.
I have a worked set of afr265s making them more like a 300 still running a 2.19 valve that make over 700 hp with a 665 lift hyd roller cam. I wouldn't get to worked up about valve size on the smaller bore big blocks
No its the issue that the only valve they offered was the 2.30 intake valve. I checked it and the 2.30 JUST barely fit the valve reliefs. This is what I was concerned about. I wanted the smaller valve so there was no question. @@bure4me
Have you seen these people that add the golf ball dimples to the inside of heads? Turbulent flow with increased wall resistance seems to be the plan. With a pressurized intake turbulence is the only thing you can count on. We keep trying to reduce the turbulence but we haven't tested corrugated walls with the grooves perpendicular to the flow. If the grooves were only 0.015" deep the swirl should increase the flow.
I did a video about dimples and flowed a head and it lost flow if I remember right. Dimples are for golf balls not cylinder heads.
I know here you are just running and Oval intake unchanged here, but would you gasket match one if you had it in reality for best performance? Does someone actually make a Roval port intake?
Thank you for your knowledge and videos USA 🇺🇸 USA 🇺🇸 USA 🇺🇸 USA 🇺🇸
I really think the 290 head is aimed for 4 inch stroke and the 317 for 4.25 stroke. Both work good.
Both 290, and 315 needed more cam and valve spring in this test. Thats the bottom line.
@@donavan2676 I was thinking along the lines of compression ratio and engine displacement. I have used the 317 quite a few times on 496 builds with low 260° @.050 on 108 and .650 to .690 intake lift and they run extremely well, at 10.25 to 1 Easy 9 second 3000 lbs street/strip cars, well set up. Fortunately for us making power is reasonably easy these days.
@@Comet-hn3gm I'm thinking about the LSA being changed to 106.what would power be then
@@davidreed6070 Likely more torque and midrange power. It will sign off about 150rpm sooner, approximately.
I purchased some Shocker 200 Ford FE heads from Jason. They were supposed to have valve springs for hydraulic flat tappet. The springs were way too high pressure for flat tappet AND the installed heights were ALL OVER THE PLACE. Absolutely no shims under the springs! They were just thrown on there. These springs that were over 190 closed and over 470 open may have contributed to my Comp Cams flat tappet failure in less than an hour of run time. This of course killed all the bearings and the crank. Not to mention the gaskets and labor. The motor was in the car not on a dyno. Not really happy with Jason and ProMaxx. Oh, and they cost a lot more than big block Chevy heads.
What octane did you use for the test?
If you gave back the compression you lost on 317 so 11:1, I would assume you would gain all what you lost to 290 roval back and properly more right?
Probably pretty close. I hope to test to find out.
Interesting test i kinda figure the roval would make power lower but the compression ratio on the big reg port like your saying if it was the same it would be the same or better. I kinda wonder if they would end up the same what causes it because of all theories the rec port should have less low end but it doesn't so would that mean the bigger cubic big block likes the big ports you think?
Interesting and appreciated. Thanks.
ON BBC, should the cam intake cam lobes or rocker ratios for the short ports be different than the long ports?
I don’t but I haven’t tested that.
Hey man one more question on the 290s did u have retrofit hydraulic lifters if yes how long were the push rods and what rockers did you use im looking to get these and am worried about push rod length? So i was thinking just do what u did lol i have comp cam retro fit hydraulic roller lifters
Always measure
Awesome vids very helpful thankyou.
Did you test both with RPM air gap manifolds? Just wondering if it made a big difference on low end torque
No. Not with the 317
YOU SAY STREET, BUT MOTORS IN THE STREET DO MORE WORK BELOW 5000 THAN ABOVE. WHY NOT PULL FROM 3000 AND SEE. ALSO WOULD THE 290 WORK BEST ON A 454 PROBALLY. TO BAD YOU CAN TO EXUASTIVE TESTS TO GET UNLIMITED DATA. GOOD WORK ERIC.
Eric: do you consider velocity? I ended up using rectangular on blower motors, or really big inch/ high rpm
Yes. But it is one of many factors to consider not the only one.
Steve Schmidt and Sunny Lenard are the 2 highest and happiest dynos on the planet.
I'm thinking if you milled the 317's to equalize compression and changed the springs to handle 7500RPM, the 317 would beat the smaller by 25+ hp.
Much more then 25 HP difference if you ran them to 7500 RPM, the 317's though need some port work to really realize their potential. We run a CNC version from FloTek that is 375cc, those make power.
so just a spring change is needed for 65-6800 rpm
Erik, did you change the jetting between the two?
no
Isn’t that an indicator that the 290 heads are better for this engine?
Seems like it pulls more fuel, in my experience that makes a more responsive engine.
What would be the ultimate head for a dz302?
Raised runner oval port
@@WeingartnerRacing Is that still a 23 degree valve or does the valve angle change with a taller port/raised runner?
Interesting video. Can’t wait to see next weeks!
Big Block Torque wins on the street..bottom line.....good job man..
Using the standard of a full point of compression equals +- 4% change in HP/TQ
11.10 - 10.25= .85
4% x .85= 3.4%
The higher compression combo has a 3.4% advantage.
SCR static compression ratio is not what determines octane requirement. Camshaft size, or more specifically when the intake valve closes at .050” has a huge impact on cylinder pressure, therefore DCR dynamic compression ratio or operating compression is how you calculate required octane.
How do you feel about cheap knock offs of well established products?
The compression is only worth 2.0%, but it doesn't really show anywhere. I think the 290s is the right size for a 496.
The 290 "comes on" much earlier and hangs with the 317. Dynos don't measure response or drivability, which the 290 would win. Maybe you could cam the 317 heads a little better, but then you could do the same with the smaller heads.
fwiw, I say Moly, but the Germans pronounce it like "mall-uh".
I hate it. China designs nothing. The stuff being copied isn’t by some Chinese company sending a spy. It’s by an American stealing another Americans idea to have it made there. It sucks but there is no way around it now.
I dont understand why they fill the top of the port and not the bottom. It maked no sense to me.
oval port just need the ports raised 1", fast track to 600HP
Why not modify that 290 head and see how much better it can get put a 2.300 valve in it, better valve job and better Valvespring setup, it’s what almost 30 cc smaller but only 7 hp behind regardless of having more compression ratio that’s pretty impressive, I wouldn’t think it would need any kind of an octane booster at 11.08:1 I’ve ran 11.3 many times on 92
I might do that also.
Good data but man could you make the video a little more interesting than pointing the camera at two heads for the entire time.
It’s not an oval port. It’s actually a 🔲square port, with rounded corners
Hence the name “Roval” which he explained like 75 times in the last two videos
@@DSRE535 Didn’t hear it. Don’t care
@@regsmith7604 no one cares about your opinion..
Yes, it is just like the Edelbrock E-street heads, basically the same heads on the 502. Chevy makes a dual plane to exactly match the "roval" ports.
I know here you are just running and Oval intake unchanged here, but would you gasket match one if you had it in reality for best performance? Does someone actually make a Roval port intake?