[Steve C.]

Paul you are correct at one time Jim did run a Holley carburetor with the RPM intake, I've seen. However I have no reported ET & Mph with it that way.
The ET & MPH I reported above was with the Q-jet on the specially prepared Edelbrock RPM intake.

[PAUL K]

Originally Posted by Steve C.

Paul you are correct at one time Jim did run a Holley carburetor with the RPM intake, I've seen. However I have no reported ET & Mph with it that way.
The ET & MPH I reported above was with the Q-jet on the specially prepared Edelbrock RPM intake.

Yes I understood what you were saying. You usually have to work a factory manifold to keep up with an RPM. The RPM seems to shine in the 500-600 horsepower street builds we do around here.

[Steve C.]

Jim's brother Floyd Hand in his 1966 LeMans with a 455 also ran a Edelbrock Performer RPM intake at one time. Approximately 3750 lbs in race trim.

Performance: 1/4 e.t. was 11.86 seconds @ 112.9 mph with a stock cast iron intake manifold. A different day and track with Performer RPM manifold he ran 11.76 @114.56.
Note I did mention different track and different day. In all fairness intake manifold testing should be done at the same time.

As I stated in my post #4 .... test it with the Performer RPM intake first then with the stock iron intake. Each combination will be different.

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[scott70]

i think I remember seeing on the SD site that they saw a 12hp gain between a stock iron intake and their ported version. Ive been thinking about pulling mine and having him port mine.

[NeighborsComplaint]

Paint the performer and put a dual snorkel air cleaner on it.

I left mine aluminum but installed a repro '71 Z28 air cleaner that works on the Holley and looks stock. I also custom bent a fuel line with a distribution block like the BBC had to make it look like stock.

[Skip Fix]

At the HPP Shootout Floyd and I were at they wanted some street 11 second cars. It was at the PSN in 100 degree weather so it was tough for us to get there. Floyd had to swap a Holley on to do it.

[ponjohn]

Originally Posted by scott70

Just freshened my 70' 455 a few months ago. 9.7-1 comp,stock port matched 70' iron intake,RA4 sized HFT cam,rhoads lifters,Cliff Qjet, #64 heads 254 cfm on the intake,1 3/4" headers. Dynoed 491 HP @ 5200 ,,, 570 lb trq. A stock iron intake is very capable.

What cam exactly?

[ta man]

Originally Posted by Skip Fix

At the HPP Shootout Floyd and I were at they wanted some street 11 second cars. It was at the PSN in 100 degree weather so it was tough for us to get there. Floyd had to swap a Holley on to do it.

I have all those old mags..I remember those shootouts..best part of HPP back then. I hoped one day to be quick enough to be involved in one.

[NeighborsComplaint]

Also, mounting a Holley on a spread-bore intake with an adaptor is not a good idea from a performance standpoint though there are a couple adaptors sold that have tapered primary bore transitions that work better. Unfortunately, they also add about 2" in height.

You already have the intake and carb and the Performer RPM is a good intake even for a lightly modified motor.

You could try your hand at grinding off the Edelbrock logo before painting with Rustoleum Hammered finish paint which will impart a painted cast iron texture over aluminum. The light blue is a very close match to the Pontiac Silver Blue Metallic engine color.

Here what lurks beneath the dual snorkels:

[Cliff R]

"The ET & MPH I reported above was with the Q-jet on the specially prepared Edelbrock RPM intake."

Jim ended up exploiting the Q-jet, custom spacer and iron intake until it ended up running quicker than the RPM intake and Holley if you factored in the D/A, but no one wants to here that then or now.

Instead folks ignore all that and focus on the single event at Ark City where the Holley and RPM powered Jim's Wagon WAY quicker in the "mine shaft" air available that weekend and nearly perfect track conditions.

Matters not in the big scheme of things, but we have FAST Class Pontiac powered cars into the 9's over 130mph with cast iron intakes on them.

I also did a back to back test on a very well prepared 428 a few years ago and tested 3 intakes. An RPM port matched only, my "modified" iron intake that Dave at SD has a scan of to modify them, and a modified HO "re-pop" intake.

The cast iron intake made 497hp, the RPM made 491hp, and the HO made 487hp. There were no other changes done with that testing, just swapped them back to back to get the results.

So with that in mind as good as the RPM intake is, you aren't using it's potential for most of these engine builds till you get to at least 500hp......IMHO.......Cliff

[scott70]

Originally Posted by ponjohn

What cam exactly?

cam

dyno video https://www.youtube.com/watch?v=-7vZwbCQlUw


The furthest thing from "stock" on my engine are the heads cnc port job by SD performance.

[Steve C.]

Cliff is correct a factory iron intake can and do run well into the 9's.
Jay DeLaigle's 1974 Trans Am with his '455 FAST ENGINE' stroked to 501 cubic inches is a good example. Take note of the work performed to his intake....

1974 Pontiac EGR cast iron intake, Ported and flowed by Wilson Manifolds with support from Jon Kasse racing engines and SD performance.

Wilson Manifolds , top dogs in the intake modification industry. Pricey work I bet !


Cliff and Paul K comments are well taken, the RPM intake can shine above 500 hp.

[Steve C.]

"After a successful season in 2000 with the new 473 engine and finding out what it's performance capability was with after market parts, Jim decided to revert back to a stock style cam and induction system."

"With that in mind, off came the the Edelbrock RPM intake, the Holley carb, and out came the Wolverine 234/244/112 LS camshaft."

"Jim reinstalled his trusty 1969 Q-jet and modified the intake. Specifically, the intake runners were cleaned, straightened, and enlarged to standard gasket size for better airflow."

"This performance level compared favorably to the events in 2000 with similar weather where the car ran in the 11.53 @ 115.5 range with 1.59 60' times."



Jim Hand's Performance Changes in 2001

https://pontiacstreetperformance.com...ld455jh01.html


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