Cutting the divider down on dual planes has been done for years. In racing classes that require a dual plane especially. But we have found with dyno tuning that .5" is what works best. Not .75 or 1".
According to Mondello & High Velocity Heads(inventer of the tapered spacer originally for Xfinity cars with the 390 cfm carb), cutting it a minimum of 1/2" improves it & Mondello said "the more, the better". I had uneven mixture from cylinder to cylinder even after cutting the divider down a little over 1/2" so I bought the HVH 2" tapered spacer. The spacer evened out the mixture & I was able to lean the carb down 2 jet sizes on both ends. Emissions might be the only reason why Edelbrock has a full height divider on some intakes & a cut down divider on others.
Ha! I didn't know this was a "thing", with a router I mean. I did this last night, with a single cut nonferrous carbide burr, to an Edelbrock 7505 dual plane dual quad intake for the FE Fords. However I did it to give a common manifold signal to the dual EFI throttle bodies. I've experienced drive ability issues with EFI throttle body systems, Sniper, Fitech, FAST, etc., on dual plane manifolds on other builds. Knocking down the divider has been a remedy. I've not been able to test for performance gains or losses. Maybe one day.
If I do it again I’d get a milling bit instead of a wood bit, at the time the only thing I had. Good to know this helps with efi if I go that direction in the future.
Another reason a taller spacer helps on a dual plane is it gives the air fuel mixture the chance to slow down slightly to make the sharp turn into the runners without fuel drop out. Air can easily make the turn but fuel can't.
i used a rpm air gap on my street 400 in windsor. had it ported and cut. nice manifold. then i had my vic jr manifold completely ported and then added a 1" open spacer. woke that motor up. seem like that rpm manifold kind of choke it. was good down low but mid range top end this motor loved the vic jr better. feed it. 400 cu in needs some air. air gap def was a good street manifold for low end torque.
I agree. I've ran dual plane intakes on 327, 350 and a 406, they all preferred the victor Jr. And also liked a 1 inch spacer. Dual plane intakes are good for street cars with taller street gears, but a quick car likes gears and a single plane intake. I've got a 383 on the stand now with a home ported victor Jr intake and the car has 3.73 gears and a 3,000 stall. I can't imagine a dual plane being better except on the bottom end and up to 35-4000 rpm. Maybe better on gas mileage, but not all out power. That's my two cents. Lol
I've got same intake and gonna copy ya.. got a edelbrock air gap but gonna swap to my performance products hurricane. I run a 318 in a dirt late model and twist it to 7000-7500 and as u know nobody makes a single plane for Magnum style heads.. well Indy does but I'm not spending $500 plus shipping.
You just proved to me that a template is not necessary to cut down the divider. Thanks for chancing it first. The Holley Sniper Throttle body requires the space under to be cut down.
Hello John, I am going to install a Sniper onto an edlebrock performer intake myself, (351m), and wanted to notch the ridge as well. Should I stop at 3/4” or 1”, or should I take it to the base? What kind of performance are you talking about, and how did your Sniper adjust to the intake?
I did this to my Eddie RPM intake on a LS 6.0 just to make the Holley Terminator TB work. They are OK manifolds . Manifolds like the Fast lsxr gain 50 HP over the Eddie though. Not joking.
Sir: check the value of dirt and debris that may collect in the K&N filter. The reason why is because air flow restriction goes way up in a short period of time. I think it's because of the oil impregnated material on the filter. I just thought I'd leave you with that message....later!
should buy a 4 hole spacer plate then cut the center out to match the top of intake to match the divider so you don't have the triangular flat spots where the carb would normally sit
Good move with the router. . .but for anyone watching, if you try this, BE CAREFUL, I was a woodworker for 10 years, and if a router "grabs"(can easily happen on hard aluminum), it can come out of your hands, and easily puree any body parts it comes in contact with.
I bought a China dual plane ordered and thermostat and thermostst housing for a 318 but thermostat is too small hosing is smaller too. What did you use?
I did a little research most went 3/4” to 1” down. So that’s where I decided to stay. I figure if you start at 3/4” and test it’s easier to remove more afterward, harder to weld it back and then shape it.
Hello can you help me? My motor 350 is not really mod. Only cam 262/270 headers, flat piston, heads stock little port. Can i use the intake edelbrock performer rpm?? Or for me is better performer?? Thanks alot. 👍👍
All depends on what your doing, if you want torque use the performer, if you want higher RPM use the performer RPM, the Performer RPM probably goes up to 6500 rpm where the performer only goes to 5500 rpm. It depends on what your doing, truck/car? Off road/street driving? etc.
I watched an episode where they did the open vs 4 hole on a dyno And there was slight improvement, I did try it and I didn’t see a difference when I did a couple back to back runs. I still have them and I might try it again one day.
You want more rpm ? Use a single plane intake and around a 3500 converter, and if ur gonna boost it then the single plane intake will flow alot more from 3000 rpm and up. They are usually designed for 3 to 6500 rpm. Don't forget to match components.
Hey John, building a dodge magnum with limited intake manifold options this was the best route. If I had a sbc or sbf then I’d go single. But I still want some low end grunt and increase the rpm a bit.
I tried 4 hole and open both, honestly at the track no change. Remember they are controlled environment and perfectly tuned. I made I think 4 passes open and 4 passes 4 hole. Left it all alone and I didn’t see any change with spacers.
When I made this mod to the intake I also switched carbs, added a rmvb to the trans, and lightened the car. So I can’t say all I did was this and put it one for an apple to apple comparison. Did I think it helped, yes.
I added one as well, it’s all about plenum volume. Removing the divider also helps with rpm. So between the two I was able to improve. But now I’m running a 100 shot of nitrous so no spacer when I do drag n drive stuff. At my local track I’ll run the 1” spacer.
@ShopDogFabrication it's a simple tuning device, I've ran 4 hole 1" spacers on daily driver pickups. I like 50cc pumps too. Along with 31 shooter part throttle responce is greatly improved in heavy cars and pickups! Lean it out just a little and it was worth a couple mpg and still had great throttle responce.
That air filter Will get a kit more air along with a lot more dirt into the engine. If you are strictly racing then K&N are good. Terrible filter For a street car.
Router is all I ever used for 35 years.
Cutting the divider down on dual planes has been done for years. In racing classes that require a dual plane especially. But we have found with dyno tuning that .5" is what works best. Not .75 or 1".
According to Mondello & High Velocity Heads(inventer of the tapered spacer originally for Xfinity cars with the 390 cfm carb), cutting it a minimum of 1/2" improves it & Mondello said "the more, the better". I had uneven mixture from cylinder to cylinder even after cutting the divider down a little over 1/2" so I bought the HVH 2" tapered spacer. The spacer evened out the mixture & I was able to lean the carb down 2 jet sizes on both ends. Emissions might be the only reason why Edelbrock has a full height divider on some intakes & a cut down divider on others.
Ha! I didn't know this was a "thing", with a router I mean. I did this last night, with a single cut nonferrous carbide burr, to an Edelbrock 7505 dual plane dual quad intake for the FE Fords. However I did it to give a common manifold signal to the dual EFI throttle bodies. I've experienced drive ability issues with EFI throttle body systems, Sniper, Fitech, FAST, etc., on dual plane manifolds on other builds. Knocking down the divider has been a remedy. I've not been able to test for performance gains or losses. Maybe one day.
If I do it again I’d get a milling bit instead of a wood bit, at the time the only thing I had. Good to know this helps with efi if I go that direction in the future.
Another reason a taller spacer helps on a dual plane is it gives the air fuel mixture the chance to slow down slightly to make the sharp turn into the runners without fuel drop out. Air can easily make the turn but fuel can't.
I would think adding spacer and just rounding of the center divider would accomplished the same effect.
i used a rpm air gap on my street 400 in windsor. had it ported and cut. nice manifold. then i had my vic jr manifold completely ported and then added a 1" open spacer. woke that motor up. seem like that rpm manifold kind of choke it. was good down low but mid range top end this motor loved the vic jr better. feed it. 400 cu in needs some air. air gap def was a good street manifold for low end torque.
I agree. I've ran dual plane intakes on 327, 350 and a 406, they all preferred the victor Jr. And also liked a 1 inch spacer. Dual plane intakes are good for street cars with taller street gears, but a quick car likes gears and a single plane intake. I've got a 383 on the stand now with a home ported victor Jr intake and the car has 3.73 gears and a 3,000 stall. I can't imagine a dual plane being better except on the bottom end and up to 35-4000 rpm. Maybe better on gas mileage, but not all out power. That's my two cents. Lol
I've got same intake and gonna copy ya.. got a edelbrock air gap but gonna swap to my performance products hurricane. I run a 318 in a dirt late model and twist it to 7000-7500 and as u know nobody makes a single plane for Magnum style heads.. well Indy does but I'm not spending $500 plus shipping.
intake manifold fabbing is a lost art!
You just proved to me that a template is not necessary to cut down the divider. Thanks for chancing it first. The Holley Sniper Throttle body requires the space under to be cut down.
Hello John, I am going to install a Sniper onto an edlebrock performer intake myself, (351m), and wanted to notch the ridge as well. Should I stop at 3/4” or 1”, or should I take it to the base? What kind of performance are you talking about, and how did your Sniper adjust to the intake?
@@3DogsTite 3/4" is good. No need for a deep cut. What performance came to is great.
I did this to my Eddie RPM intake on a LS 6.0 just to make the Holley Terminator TB work. They are OK manifolds . Manifolds like the Fast lsxr gain 50 HP over the Eddie though. Not joking.
Sir: check the value of dirt and debris that may collect in the K&N filter. The reason why is because air flow restriction goes way up in a short period of time. I think it's because of the oil impregnated material on the filter. I just thought I'd leave you with that message....later!
I had to use 67 chamfered jets. A 600cfm Holley, with a 750 cfm bowl conversion kit to dual feed single pump.
i did something similar, except i used a grinding stone on an iron manifold, (class rules required stock iron manifold)
Thats why carb spacers usually work...
Machining down the plenum divider is beneficial....
Very good,thanks for showing your racers edge tricks....keep the vids coming please....
You could use a round over bit with the router to smooth the chamfer
I used a cut off tool and made V-cuts then cleaned it up with a die grinder, possibly faster (and you don't need to have a router).
If you were planning on running a carb spacer, then why did you mill the divider on the intake?
The spacer adds more air volume as well
Yeah, more plenum volume which will help flow more air into the runners.
should buy a 4 hole spacer plate then cut the center out to match the top of intake to match the divider so you don't have the triangular flat spots where the carb would normally sit
Good move with the router. . .but for anyone watching, if you try this, BE CAREFUL, I was a woodworker for 10 years, and if a router "grabs"(can easily happen on hard aluminum), it can come out of your hands, and easily puree any body parts it comes in contact with.
YES! B careful sharp bit and a firm grip.
Thanks for the knowledge
Awesome video. I may try this on my intake. Love the hoody btw
Did you notice any top end power gains?
I did, car runs well with it. Added a small nitrous shot as well and not having any issues.
That 2nd router bit is indeed a 45 ° bevel bit . 😳 I'm a 30 plus year master woodworker.
I bought a China dual plane ordered and thermostat and thermostst housing for a 318 but thermostat is too small hosing is smaller too. What did you use?
Sorry didn’t see this earlier. I’m Using the original 1970 318 thermostat housing.
Very nice. Are there any videos showing how much to mill the center down. Are, are we just winging lol. HAGD
I did a little research most went 3/4” to 1” down. So that’s where I decided to stay. I figure if you start at 3/4” and test it’s easier to remove more afterward, harder to weld it back and then shape it.
@@ShopDogFabrication that is so true. Any results to note yet.
On another note what can you tell me about 1966 casting for a pair of #702 heads. 98cc.
Looks like the router would work well for port matching also.....
It does, I did a video doing it to cylinder heads.
What if u drill holes and not shave it
Fermenttadoor I have no idea what would happen. Might get a whistle if you di
Hello can you help me? My motor 350 is not really mod. Only cam 262/270 headers, flat piston, heads stock little port. Can i use the intake edelbrock performer rpm?? Or for me is better performer?? Thanks alot. 👍👍
All depends on what your doing, if you want torque use the performer, if you want higher RPM use the performer RPM, the Performer RPM probably goes up to 6500 rpm where the performer only goes to 5500 rpm. It depends on what your doing, truck/car? Off road/street driving? etc.
@@ShopDogFabrication ok i understand me i want for street. Maybe need to got performer and i seel my rpm. Thanks alot.
Great video
I would think a tapered 4 hole spaerwould restore lost torque and add top end
I watched an episode where they did the open vs 4 hole on a dyno
And there was slight improvement, I did try it and I didn’t see a difference when I did a couple back to back runs. I still have them and I might try it again one day.
You want more rpm ? Use a single plane intake and around a 3500 converter, and if ur gonna boost it then the single plane intake will flow alot more from 3000 rpm and up. They are usually designed for 3 to 6500 rpm. Don't forget to match components.
Hey John, building a dodge magnum with limited intake manifold options this was the best route. If I had a sbc or sbf then I’d go single. But I still want some low end grunt and increase the rpm a bit.
Well, did you improve your ET's?
It did pick up a little rpm and was happy with the improvement. I’d do it again. I’m always tweaking.
Engine masters did all the test. Dual plane. Needed your cut out. But, your riser must be a 4 hole. You'll loose power around 2500rpm
I tried 4 hole and open both, honestly at the track no change. Remember they are controlled environment and perfectly tuned. I made I think 4 passes open and 4 passes 4 hole. Left it all alone and I didn’t see any change with spacers.
Did you modifications make a difference
When I made this mod to the intake I also switched carbs, added a rmvb to the trans, and lightened the car. So I can’t say all I did was this and put it one for an apple to apple comparison. Did I think it helped, yes.
Spacer will do the same thing
anybody ever run a open spacer and 4 hole at the same time?
I’m sure you could, I don’t have the hood space unless I used short ones. Not sure what others have tried.
I invented this two years ago. Switched my air gap with a weiand non gap and it didn’t have the cut out. Would love to see a dyno comparison.
Google Vanke modification
I would pay to see some of these channels if they would leave the music and stupid Graphics out
Why not put a 1" open spacer on it?!
I added one as well, it’s all about plenum volume. Removing the divider also helps with rpm. So between the two I was able to improve. But now I’m running a 100 shot of nitrous so no spacer when I do drag n drive stuff. At my local track I’ll run the 1” spacer.
@ShopDogFabrication it's a simple tuning device, I've ran 4 hole 1" spacers on daily driver pickups. I like 50cc pumps too. Along with 31 shooter part throttle responce is greatly improved in heavy cars and pickups! Lean it out just a little and it was worth a couple mpg and still had great throttle responce.
nice vid but mods to intake would do nothing for any engine more then likely you lost power. its all about porting heads.
I didn’t loose power, I gained some. The rpm helped it provided helped.
Dyno test show it ain't even worth doing carb spacer works better
Another could be good video screwed up with a want to be sound engineer (all the extremely loud so called music).
Why these ignorant people put loud music on a video???
Why are they ignorant ? I find the music annoying as well but don't see a need to make a judgement of their cognition.
That air filter Will get a kit more air along with a lot more dirt into the engine. If you are strictly racing then K&N are good. Terrible filter For a street car.