Why can't Edelbrock produce a decent trans am manifold?
 

It's common knowledge that the pontiac edelbrock performer is not as good as even the stock cast iron pontiac restricted secondary manifold.

I took a mold of on of the runners to see what we were dealing with. The runner dimensions near the plenum are 1.275 by 1.720= 2.19in2, compared to 1.1 by 2.07=2.277in2 for the stock 6x cylinder head port sizes.

Why on earth would edelbrock produce a manifold with runners 4% smaller than a standard pontiac head port?

I'm kind of stuck running the performer because I've got the aluminum D port heads, and I'm trying to keep it looking stock so torquers and RPM manifolds are out.

All edelbrock needs to do is take a stock 455SD manifold and recast it out of aluminum. I'm sure they'd sell lots
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I put an edelgarbage on my ta, stock one was better. One day I’ll swap it back. First, you gotta file off their logo and paint it. That’s what I did.

The SD455 manifold would be a poor choice to copy. It has a complicated EGR system and a restricted plenum because of it. No need to copy the aluminum HO/RAIV manifold as they were being made by GM at the time.

The Performer manifold was designed to be an improvement over OEM manifolds on mostly stock 75-79 smog motors and it usually did just that. It came out in the early 80's when there were millions of engines like that, so Edelbrock wanted to make a manifold for those potential customers. The flat carburetor flange could be an advantage on almost every vehicle out there but the Trans Am.... Fwiw

The days of Edelbrock developing Pontiac intake manifolds are long behind us now.

For most people a ported iron or reproduction RAIV or 455 HO intake will easily handle the job and fit exactly like it needs to for cars with Trans Am shakers and low clearance fiberglass Formula hoods.

The only company that’s currently designing and putting out different new Pontiac intakes is Kauffman Racing Equipment or KRE. Maybe they’ll consider producing a Trans Am specific intake if they find the demand is great enough.

Edelbrock sadly is no longer a player, especially so since being sold after the passing of Vic Edelbrock Jr. to venture capitalists who have zero intention of expanding their product line.

If you scanned one, there's great things going on with 3d printing these days, carbon is crazy expensive but the point being, if you want it bad enough, you can make a better one.

Hell I made a 12-1 bolt on crank trigger kit for us, not cheap to design or fast but it's awesome to have done it. I guess if could recoupe if I offered it for sale so you could too.

If I win the lottery, I'll have someone make me a manifold using whatever technology

I don't have a problem with EGR, or exhaust crossovers. My (3156?) performer has EGR, and so would any reproduction I would make. I also need a crossover because I live in a colder climate.

I've heard the Ram Air reproduction is not very good, but I might buy one and graft a performer crossover onto it, and fake an EGR boss for authenticity

As far as normal driving, my performer/stock qjet runs extremely well. It starts easy, runs smoothly warming up, and has reostatic response in normal driving. My beef is that I'm likely losing 30hp/750rpm at the top end

What’s your hp goal?
If you’re not looking to make over 430 hp then the performer will do that, and even with 455 cid under it.

A 800 cfm Q-jet and a 1/2” spacer is the what’s needed to top 400 hp.

If we are pretty universally stating that the stock intakes are better, and you are looking to stay stock height. I don't understand why you are feeling like you are stuck using the Performer?

Why not invest a little bit of money into a ported stock intake and use that?

Exactly this.

A ported later EGR iron intake is as good as anything up to about 500 horsepower. Just because your heads are aluminum doesn’t mean to have to go to great lengths to put a specially fabricated aluminum intake on that really buys you nothing power-wise and saves a paltry 20 pounds which on a 3700 pound car amounts to nothing.

The ‘73-‘74 EGR intakes with the massive passages underneath are the heavy ones. The ‘75 and up ones are much lighter and even with their D-shaped secondary openings perform on par with even the pre-EGR intakes.

Don’t most people with aluminum heads interested in performance use a RPM intake and an aftermarket drop base air cleaner on second gen’s?

When I was building my RAIV motors for NMCA I ordered a Performer (Super Shops) because Edelbrock does advertise them as "better than stock" . Flow bench showed otherwise compared to my HO intake. I even call tech and they just spouted the same thing even though I told them no it flows worse. Granted not bad but less. Luckily I could swap it for T2 to use on another motor.

Weird deal the 73 SD intake actually picked up flow over not intake at .3! Less HP hit in factoring with iron vs aluminum factory intakes so I could pull some weight out but car ran the same. And that 45 lb intake with that crazy EGR stuff was heavy. The later EGR manifolds not quite as heavy.

On a TA with a Shaker a Performer is 0.5" lower in back than a factory intake so affects the Shaker appearance. and using an angler spacer with the long bolts up fron on a Q jet is a little difficult!
I used an HO on my first E head motor for awhile until a found and extra Shaker base to tweak for a Holly. Then swapped a T2 on it. The HO was restricting it.

Someone on another forum recently posted the intake manifold below. He said that it’s lower than a Performer RPM and better than the Performer. It looks like a clone to me but no idea what it was cloned from but might be worth a shot?

https://www.ebay.com/itm/11653460384...d48b6593ad1540

Looks like an RPM clone to me.

Me too but the poster said that it fits under his hood just fine.

https://www.gtoforum.com/threads/alu...7#post-1052387

Poor man's Extrude Hone ?

Muriatic acid available from Home Depot.
Highly corrosive it will "acid etch" the inside of aluminum intakes and remove material. Contain it inside the intake by using stainless steel plates at the port openings.

On one example using the Performer RPM intake the divider was about 0.200" thick before and about 0.070" after.
Parting line flash was removed inside the plenum area. Material from the intake runners is removed.
Amount of time and/or changes with fresh solution will affect amounts of material removed.

( Side note: Info intended as conversation only. I'm not suggesting to anyone to use this method )


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An aluminum manifold in a colder climate means faster, leaner warmups. When i first bought the car in 1975, the EFE stopped working. The car would not run. With an aluminum manifold, EFE is not needed. I'm running fairly lean: 15 AF at idle, 16.5 at 70mph for fuel economy and emissions.

You are likely right, but running a cast iron manifold strikes me as archaic

I think I'm a bit of an eccentric. I had also bought a holley dominator in '76. I tried running it with the q jet and it was a dog. I even went to holley in detroit and talked to the engineers to find out why. They said "use a holley carb" so I put om a 600 holley double pumper. It really woke the car up. I used that until a decade ago when I put in the performer I had bought in the early 90s. The holley performed great, but I missed the Q jet moan. There is no perfect solution.

I think I'm mostly annoyed that edelbrock missed the mark so badly

What are you meaning colder climate? Do you drive her through winter? I am up here in BC Canada. And wile I don't drive my TA in winter, I do when it's cold spring/falls Performer intake on a 455HO stroker with 800 Qjet manual choke and she runs just fine

How happy are you with the performer in the upper rev ranges, ie, 5-5500 rpm?

And yes, with the performer it runs great under all conditions, including warmup with the automatic choke. I've got a wide band AF meter. When I start the car, it says 11:1. By the time I'm at the end of my street, 14:1. A couple of blocks later, 15:1

Perhaps I'm demanding too much to expect optimum power too.

Curious: Is there enough meat on a cast iron intake flange to use on a high port head? I unwisely tossed the restricted secondary cast iron years ago in disgust.

The factory manifolds are already being cast out of aluminum for years. Just get one of those. I can tell you they work a hell of a lot better than the performer and they accomplish a few things for you. They look stock because they are, they will fit the shaker without jacking stuff, it's aluminum so it matches your heads, and they perform as good as the iron intake.

I've done back to back testing with them out of the box on a high 12 second car and it was identical in et and mph to the factory 70 RAIII iron intake.

Easy solution

I've heard that crap so many times that, "if you want a good running engine that it has to have a holley carb on it", what a load of crap that is.......:gag:

My personal experience is running 400, as well as 455 second gen T/As with a street dominator intake for customer cars, autocross cars and my own personal car with only reworked Q jets on them contradicts whoever told you only a holley carb will give you good performance on that intake.

If it were true, why would holley make the carb flange so you can bolt a Q Jet directly to their intake? The intake doesn't know what the brand name of the carb it's bolted to does it? The metering of fuel is all that the engine cares about.

Super stock classes run in the 9s and are required to run Q jets on them. so much for restricting performance.

The Q jet has much more versatility built into it than any other holley carb does and a ton more money spent on developing, and testing them. The Q Jet is also very adjustable to allow it to fit so many applications, and it seems that many in the performance arena have no understanding of the complexity of the carb. If you don't understand how something works, you surely can't expect someone to make correct adjustments to make it optimum in a performance application.

If you want an aluminum intake that will allow the scoop to be functional an Edelbrock P4B will fit the bill. However it isn't going to flow any more air than the already scienced out iron factory intake.

The truth is Pontiac engineers made such a good intake that the aftermarket has nowhere to pick up performance over it in a 2 plane intake. That's why the single planes can pickup performance over a 2 plane when it comes to more than a street engine, say above 500 HP. The factory dual planes are already very good as designed.

FWIW, all my racing efforts were topped with Q jet carbs, be it drag racing, circle track, or autocross. As you can see in my signature pics I was successful using the Q Jet in all the venues. I wish I had a dollar for every time I was told by a competitor that my cars would run much better with a holley on them, how much better could I run than first place? LOL.....:D

I quit listening to recommendations from people that weren't very knowledgeable decades ago, all they do is hold you back.