Single plane vs. dual plain [Archive] - Chevelle Tech

: Single plane vs. dual plain

forever young
Feb 20th, 08, 12:22 AM
Basic questions need to be answered for me. Help. I am building my 402 right now and it will be for the street. I am using a voodoo hydralic roller cam and running 10:1 comp. on a 331 rear - 4 speed. ok what will serve me better and fit under a cowl hood on my 70 SS, A quadrajet, holley, carter? what about high rise, single plane / dual plane, aluminum / cast iron? what are the best in performance 1500 - 5500 rpm range?

Thanks for the help.....Roland in NY:confused:

Bob West
Feb 20th, 08, 12:38 AM
Edelbrock Performer.

Feb 20th, 08, 12:48 AM
Holley 750 3310, or Holley SA 770, Performer intake. But you will get the power bug, so you might as well get the Performer RPM.

Feb 20th, 08, 2:08 AM
Holley 750 3310, or Holley SA 770, Performer intake. But you will get the power bug, so you might as well get the Performer RPM.
I agree :yes:

Feb 20th, 08, 2:47 AM
I found in the past on my 355 SBC powered Vette, that the Edelbrock Performer RPM (not the air gap one) as well as the low-rise single plane Weiand "Team G" manifolds performed the best out of the ones I tried on the car. However, since I didn't use a choke on my Holley carb, I also found that the Performer RPM manifold was a bit more street friendly because it had an exhaust crossover duct through the middle that served to warm up the intake quicker than the single plane Team G manifold did, since the Team G did not have the exhaust cross over. So with the Team G single plane manifold, the engine would run lousey during the first 15 minutes after start-up. And on the nights when the temps would drop into the 50's and sometimes even in the 40's, it was very noticeable. With the Performer RPM intake, it was only a bit shakey in the way that it ran for the first 5 minutes.The Performer RPM was also decent for throttle response beginning at 1,500 RPM,whereas the single plane low rise Team G didn't begin to offer throttle response until 2,000 RPM.

Feb 20th, 08, 6:57 AM
IMO, for a fairly mild street 402, I think a q-jet would make a real nice carb. When setup properly, they are very reliable, great throttle response and mpg's and still rival a Holley in the power department. Sean at SMI can taylor a carb to your specific engine/drivetrain combo. Very reasonable prices. I think a Stage 2 carb would best suit your needs.

As far as intakes, a Performer would work well, but I would be more apt to look at the Performer RPM Q-Jet manifold. Same as the regular Performer RPM but setup up to accept a spreadbore carb.

72BB Nova
Feb 20th, 08, 7:29 AM
I would look into a Q-jet. Sean at SMI did one me a about 4 years ago and it was a great running carb. Replaced a 750 Eddy and there was absolutely no comparison between the two. Throttle response was very good and was very reliable. This was on a 383 with a HR cam 219/227 @.050 lift was .510 on a 110lsa performer rpm, and sportsman heads. It was a 4000 lb car with a 700r4 and 3.42 gear. Best time was a 13.70 @ 101 mph. Great carb.

mr 4 speed
Feb 20th, 08, 8:36 AM
But you will get the power bug, so you might as well get the Performer RPM.

There was no difference in ET or MPH at the dragstrip when I swapped from a Performer 2-0 to an RPM on my 454 :)

Feb 20th, 08, 8:42 PM
What about running edelbrock Air Gap on the street? I just bought one to replace my current performer RPM.

Feb 20th, 08, 8:51 PM
What about running edelbrock Air Gap on the street? I just bought one to replace my current performer RPM.IMO, and based on my own experience, with the air gap, I would highly recommend running a choke on the carb since there isn't a heat crossover in that manifold, unless you're only gonna drive the car when the air temps outside are 80+ degrees even at night time. If there's any chance that some nights that you drive home, the air temps will be in the 60's or 50's, then the air gap w/out a choke on the carb will cause the motor to stumble and hesitate for the first 15 minutes of operation. If that wouldn't bother you, then it's no big deal, but that's the way it was on my 73 Vette that had a 350 engine. I tried 5 different manifolds to test out which was best.

Just keep in mind that it wouldn't matter if you happen to have aftermarket cylinder heads that do NOT have ports in them for the heat crossover. Because if they do not, then even if you had a manifold with the heat crossover, it wouldn't be any different anyway since there wouldn't be any exhaust heat going through the crossover anyway.

Mike Feudo
Feb 20th, 08, 8:53 PM
Don't use a BB Performer on anything besides a motor home. With 3.31s you will be better off with a Q-jet and a dual plane that has runners the size of the intake ports.

Feb 20th, 08, 11:49 PM
I tried 5 different manifolds to test out which was best.

What did you end up going with?

Feb 21st, 08, 1:22 AM
Single Plane for racing
Dual Plane for street

Feb 21st, 08, 7:32 AM
I was just going to mention Weiand's old 8005 dual plane as being a dandy for a Q-Jet, imho.


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Bob West
Feb 21st, 08, 7:54 AM
Single Plane for racing
Dual Plane for street

I would argue that point!! Ede Performer RPM on 505 pumpgas cubes, running low 10's ;)

Feb 21st, 08, 8:34 AM
What did you end up going with?Walter, there were other considerations with that car at the was a Vette which had a stock hood, so hood clearence was a constant and ever present concern, since there really wasn't much of it. But another factor for me, was that I ended up using AFR heads that didn't have heat crossover ports. So I ended up using a low-rise single plane manifold. it was the "Team G" one from Weiand. I noticed that it gave me an additional 300 RPM of power up at the redline than the Edelbrock Performer RPM did, but it also raised the point where the throttle response began about 400 or 500 RPM more than the RPM manifold did. So it was a trade-off.

But because of the heads that I ended up using, the heat crossover on the Performer RPM manifold wouldn't have been functional anyway. The Team G Weiand manifold also had such thick walls, that I had to shave it down a little bit in a couple places for valve cover clearance. No big deal though.

forever young
Feb 21st, 08, 9:35 AM
Ok, from all your great opinions and imput I am now thinking the RPM performer for my usage. I will be mostly street run with an occasional tow to the strip. Now as far as carbs. goes, I always ran Quadrajets and was successful. Those tiny primary's keep me cruising affordably and the secondaries always seemed to act as the afterburners. What size would I be looking for for my motor on the performer? I also want the choke to work.
The only other thought would be the factory cast iron manifold, what can this produce with the quadrajet? I want this manifold at the very least to stay with the car as its original piece. Thanks,,, Roland in NY

jeff swisher
Feb 21st, 08, 10:05 AM
my friend and racing buddy had an elky with a 355 and a 204-214 on a 112 cam with a Q-jet that i tuned with a Performer RPM intake it ran great shift at 5500 rpm he decided since it was a mild engine he would put on his eddy performer intake and use the RPM later, for his trans am

I swear he put a stock 305 in it that thing was a putz after the intake swap I tuned, and tuned on it never got any better i have never seen or felt that much loss in power

a modified Q -jet intake will run circles around a performer intake
as far as stock vs performer i do not know

Feb 21st, 08, 11:41 AM
You say your primary use will be on the street. For simple, reliable, bolt on and go, go with the Edelbrock Performer with matching Edelbrock carburetor 750 or 800avs.

Feb 21st, 08, 2:00 PM
i ran a 396 on the street for 12 years or so and the best street intake i found was the rpm intake i had tried a dozen or so intakes thru the years. this intake really responded well in a heavy car and showed up in my time slips. of course i like holleys so that is my preference.

stay away from the performer intake what a waste of money! you might as well run the stock cast iron intake.

not a big fan of any of the eldebrock carbs yuck! i wouldnt recommend them to anyone serious about performance.

q-jet would be nice as long the carb is in great shape and works well. to me that just dont seem to have that appeal of performance statement. can you see two q-jets sitting on a tunnel ram or a blower............i see them as a great choice to try and "hide" your hp output in a sleeper.