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darom 11-01-2004 02:16 PM

stock vs. aftermarket intake
Guys, need your advice if it is worth spending money or not on an intake.

A friend is selling his stock GM 1980s BBC cast iron intake off a 454 truck pretty cheap. Should I get the Performer instead (off ebay, for ex.)?

Here is the engine: 69 El Camino, 454 engine, 750 cfm Q-Jet, stock oval port heads, stock springs, Crane Max cam duration: In: 204, Exh.: 216, Lift. In: .484, Exh. .515, LC: 110 (rpm range 1500-4500), 3.08 rear end, power brakes, 2000rpm converter and somewhat beefed up TH350.

Will I lose a lot torque/hp by putting the stock intake for this almost stock engine combo?


fried_guy 11-01-2004 02:23 PM

If you want to help out your low end torque I would personally put on the Performer 2-0 manifold. It has a RPM range of idle - 5500 which matches your cam perfectly. Of course I am a STRONG edelbrock performer manifold supporter (as a lot of us are), so I could be biased.

poncho62 11-01-2004 02:30 PM

Depends on the price.................and, what do you have on your engine now. A stock 69 BB manifold is probably better than the 80s one. If you don't have one, and the 80s manifold is free, fine, but the Performer is not expensive. I would go with that.

darom 11-01-2004 02:35 PM

Thanks, guys, for the input.

I bought the engine without an intake. I saw one Performer on Ebay where the guy did a $250 porting job to it. Is it really necessary? Can you port a stock one since it is cast iron and probably has a lot of 'meat' on it? Has anyone done it?


fried_guy 11-01-2004 02:53 PM

Porting a manifold is pointless unless you have the heads ported and it's a high performance engine. Too much porting of the intake can cause poor fuel atomization which can actually hurt your low end too.

darom 11-01-2004 02:59 PM

Sounds logical. Thanks.

What about this intake?

Are these Power+Plus Cyclone Manifolds any good? Does anyone have any flow data on Edelbrock, Weiand etc. manifolds by any chance?


fried_guy 11-01-2004 03:10 PM

That looks like a performer knock-off. I can't say whether it's good or not as I've never used it or seen it used. But it's probably better than a stock manifold.

spinn 11-01-2004 07:03 PM

i would be skeptical. the crosswind(air gap knock off) had significant port mismatches.

fried guy doesnt seem to like porting..?..i like to do a good port gasket match blend it 2-3 inches into the manifold(and heads).i dont feel a difference,but every little bit helps,and thats performance.

performer is a awesome street manifold. i have been surprised by the engines beneath them. SURPRISED!!!

darom 11-01-2004 10:18 PM

Thank you for the feedback. I will start looking for a good deal on a Performer intake.


benwantland 11-01-2004 10:51 PM

I put a performer intake on the 360 FE in my friend's ford truck, and the ports on it were way smaller than on the heads (they were huge!). Anyway, there was a paper in the box of the intake saying that the ports on the head were too big, and not to hog out the intake, because the runners were optimally sized to keep velocity up at low speeds on the engine, which makes sense. Granted, there would be a bit of turbulence going from a smaller runner into a larger intake port, but that probably would help fuel atomization anyway.

My point is, the people who make the intakes do think about exactly how they size those runners, so think twice before grinding on 'em.

Max Keith 11-03-2004 12:46 AM

It all depends on how much he wants for the steel intake. If you can get it for say $50, go for it, then put a 1 inch spacer between the carb and intake, the kind with 4 holes in it, not the open ones. You will find this to be very viable option to $180 or more for an aftermarket if you are in the low bucks area.

I also concur with the port matching if you are pulling your heads off.

Port matching could be a misnomer here. What I recommend is to just do a 45 degree bevel grind around the port opening in the head. What this does is alleviate the possibility of having any core shifting of the head or the intake so that the ports misalign. You dont want to take off a lot of meat. The idea is to in effect, have the runner of the intake manifold, act as though its aimed at a funnel. This will reduce any possibilities of the ports overlapping each other. I would not do any grinding on the intake itself, unless you can discern there may be a lip or casting flashing sticking into the port. If you do have to do any work on the intake side, only grind it out to where it would be the normal dimension that the runner should be. A little bit is good but a lot isnt always gooder.

You can wind up with these port misalgnments with aftermarket intakes as well.

the 45 degree bevel should only have to extend about a 1/4 inch into the port in the head.

fried_guy 11-03-2004 10:00 AM

And a word of caution... if you DO decide to port match the intake to the head (which isn't a bad thing when done right), make sure the bottom of the intake is still taller than the bottom of the head. That will help 2 things: 1. It will help atomize the fuel that's dropped to the bottom of the intake. 2. It will help slow/stop gasses traveling back up the intake on the overlap cycle.

darom 11-03-2004 10:05 AM

Great, thanks guys for good tips. I appreciate your help!


Max Keith 11-03-2004 07:35 PM

stock vs aftermarket
Fried, thanks, glad you picked up that little detail for me. And your welcome as well Darom. Best of luck and hope all goes well.

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