[wh33lman]

Edelbrock Performer RPM or 1970 Cast Iron Intake?

Besides the weight advantage, is there a big difference in performance between the 2 intakes?

Assume both are port/gasket matched, with a 800cfm Cliff's Q-jet on top and unported 87cc Edelbrock round port heads underneath. (455cu.in 11:1 compression).

[Will]

The theory behind the intended designs of these two intakes tells us that the RPM should make more upper RPM power and less off-idle torque than the factory intake.

how much difference it makes in the real world is dependent on other variables, including camshaft selection which isn't mentioned in your OP.

Given the bare minimum of information we have, I'd bet $1 the theory would be representative of actual results. Furthermore, given the nature of the evidence we do have (high compression, aluminum heads, big engine) I'd wager that the intended use of this engine and the supporting drivetrain parts would pretty much negate the loss of that off-idle torque.

[Steve C.]

A tid bit for conversation.....

Edelbrock recommends the FelPro 1233 gasket for those heads unported. That gasket has about a 2.200" tall port opening. I gave my 1970 factory intake to a friend and he found the ports were so wacky out of shape some of the ports were not capable of matching the Felpro 1233 gasket.

The port opening on a Performer RPM intake as cast should be about 2.060" tall. If memory serves me right the port opening on stock intake is about 2.050" tall.

.

[Half-Inch Stud]

When you go into turns, the alumnum manifold performs better.

[Formulas]

Under what hood ??? ... Rear gear ??? ... Intended use ??? ... Summit 2800 cam or .260 @.050 duration ??? .. Torque converter??

[ponyakr]

"... unported 87cc Edelbrock round port heads...(455cu.in 11:1 compression)..."

Just curious. I can't come up with 11:1 CR, with the 87cc heads, even with an .030 over 455, without dome pistons. So, does it have domes ?

http://www.wallaceracing.com/cr_test2.php

[wh33lman]

Thanks Will,
I was deliberately trying not too give too many specs, in order to just get some basic differences between the 2 intakes.

Steve C. - The '70 intake is gasket matched to a 1233 gasket..just slightly smaller than the openings. The 4X heads it currently sits on was gasket matched to the same 1233 gasket.


For the curious...the 462 (+30 455) is a pro-street engine recently freshened and very healthy.
It has a Victor intake, holley double pumper, HSC headers, full exhaust, gear drive, motor plate, slightly domed venolia pistons, 87cc Edelbrock round ports, Harland Sharp, roller rocker arms, solid lifters 4:35? gears, and reportly ran high 10's in a "more track than street", lightened '76 firebird with cage, chute and wheelie-bars. It was recently dyno'd tuned to just over 400RWHP. I do not remember the exact cam spec's, but it runs on pump gas. (93)

I am replacing the intake, replacing the gear drive with double roller timing chain (no motor plate), replacing the holley with my q-jet, replacing the headers with RamAir OS restos, putting in a custom 2400 stall converter,and connecting it to (currently) 3:08 gears, a heavy duty built turbo350, Pypes X-over exhaust, all in a 1981 Trans Am where I currently have about 2" of clearance from the air cleaner to the hood with the '70 intake and Q-Jet on a '73 400.

It will get to the track a few times, but first I have a long road trip planned in June.

My '73-400 is a great performer, but I have over 280,000 kilometers and 30 years since it's last rebuild and I am getting this engine for less than the price of a good short block rebuild.

[Formulas]

Well for reference the RPM manifold is approx 1.1/4 higher that stock Q'jet ... Not sure how you have 2 inch now ... If I was you I would probably keep the T-2 and space the carb up to make trans am scoop work... But if your set on a Q'jet I would use the stock cast iron manifold to accommodate the trans am air cleaner scoop set up easily...As far as basic manifold characteristic whenever internal runner size length and plenum volume increase the RPM at which it makes power is higher and they lose a bit of bottom end and throttle response generally speaking...

[wh33lman]

Originally Posted by Formulas

Well for reference the RPM manifold is approx 1.1/4 higher that stock Q'jet ... Not sure how you have 2 inch now ... If I was you I would probably keep the T-2 and space the carb up to make trans am scoop work... But if your set on a Q'jet I would use the stock cast iron manifold to accommodate the trans am air cleaner scoop set up easily...As far as basic manifold characteristic whenever internal runner size length and plenum volume increase the RPM at which it makes power is higher and they lose a bit of bottom end and throttle response generally speaking...

Actually the motor had a Victor intake...but I am not taking that...I had Torker on the brain..correction made.
I have the Turbo hood, with after market air-cleaner assembly. I measured the clearance by sticking a ball of putty on the air-cleaner and closing the hood.

[leeklm]

With engine in my signature, performer rpm and stock we're almost identical at track. Overall the rpm seemed to have an edge in et but the cast seemed to idle just a little smoother.

Both were port matched with the larger gasket

Sent from my XT1585 using Tapatalk

[wh33lman]

Originally Posted by leeklm

With engine in my signature, performer rpm and stock we're almost identical at track. Overall the rpm seemed to have an edge in et but the cast seemed to idle just a little smoother.

Yes, if I put my 98cc 4X heads from the 400 on the 462, it would be almost identical. I even have a set of Hooker Super comps on the shelf, but they were a PIA on the street. Last thing I want to do though is break up a motor that my friend spent so much time & $ getting just right...I am changing enough as it is.
He went with an aluminum Kaufman.

[Formula8]

If you are running a Q-jet, I would definitely run a ported factory intake if for no other reason than to avoid the hassle of fitting the whole mess under a second gen hood for minimal if any performance increase with your RA manifolds, 3.08 gears and automatic with a moderate stall speed.

[grivera]

Originally Posted by wh33lman

Actually the motor had a Victor intake...but I am not taking that...I had Torker on the brain..correction made.
I have the Turbo hood, with after market air-cleaner assembly. I measured the clearance by sticking a ball of putty on the air-cleaner and closing the hood.

Beautiful bird in an awesome color!

[wh33lman]

Originally Posted by Formula8

If you are running a Q-jet, I would definitely run a ported factory intake if for no other reason than to avoid the hassle of fitting the whole mess under a second gen hood for minimal if any performance increase with your RA manifolds, 3.08 gears and automatic with a moderate stall speed.

Ya...same reason I decided to go with the RA_OS manifolds after taking 2 weeks to think it over. Just did not want the hassles of headers again even though with the ceramic coating, they are within a couple hundred $.
Iron intake is already out for media blasting and I will clean up the casting marks just to make it look even better before I apply Jim Hand;s porting methods. I have the clearance for the RPM now, but my air-cleaner lid is not a "bubble-top" . So if I use the iron I can replace that lid and gain back a bit of flow.
Big decision now will be to decide if I want to cut the intake to get the best match. Gears I can change out anytime.
If we had a track nearby (nearest is 1.5 hours with no traffic) I would be trying to squeeze out more power. Heads are not ported so that option is still there.
I have over 310K kilometers on this car now, with almost every component upgraded or restored, so you can see I would rather be driving it around than waiting for a track day.

Beautiful bird in an awesome color!

Thanks. Most do not believe it is the factory color..but you polish it well, and get in the right light, it looks pretty good.

new motor...minus the headers, intake and gear drive.