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If you’re not sure about the cam in the engine, you can either:

A. Get a degree wheel and measure to find the basic cam specs.

Or.
B. Pull the cam and look for a number stamped on it and look it up.
 

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The 289/302 Performer is basically an aluminum copy of a stock manifold.
I had always heard that a Performer was basically a copy of the aluminum Cobra intake, which is to say, better than an iron manifold, but well surpassed by an RPM and AirGap.
 

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I had always heard that a Performer was basically a copy of the aluminum Cobra intake, which is to say, better than an iron manifold, but well surpassed by an RPM and AirGap.
The Performer RPM is a closer comparison to the Cobra (F4B) intake. As per the graph in 22GT's post, #4 above, the Performer follows the stock intake up to 4,500 rpm, but then stock falls off while the Performer maintains a higher HP output.

The Performer works just fine with a mild, torquey little cam like the .448/.472.
 

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The Performer RPM is ever so slightly better at high RPM than the Cobra. Of course, the 289HP came from the factory with the iron manifold you are replacing.

View attachment 764416
Wow.
Look how sharply most of them drop off with the Weiand leading the pack...
 

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Performer works just fine with a mild, torquey little cam like the .448/.472.
Wouldn't bother with it with even on that small of a cam. Stump pulling 289s and 302s are a myth. They're always dogs. I'll put my torque curve- at any RPM- up against any 289 or 302 with that manifold.
 

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That is interesting. Every time someone inspects the engine they find out it has like 1980 heads and 7:1 compression. But you find pop up pistons, 351w heads, cam "too big". You may have a beast there. Those heads were the hot setup way back before aluminum heads came along.

I would at least measure the cam. It's pretty easy to do with a dial indicator and degree wheel. And definitely put on the edelbrock rpm and headers. Of course with the manual trans you can run any size cam you want. I would get that thing going and see how it runs like it is.
 

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The 289/302 Performer is basically an aluminum copy of a stock manifold. It's pretty bad. If you were going to put a 4bbl on a stock C-Code and stop there it's probably fine. Or if you have a stock A-Code and want to lose some weight. Otherwise a very poorly performing manifold in any other environment.
The graph is really telling. Lot's of area under the curves of both HP and TQ. I see zero downside to an RPM vs standard performer. You don't really lose anything down low and gain everywhere. As @BlakeTX said the RPM and RPM Air Gap basically perform the same...the air gap just looks cooler under hood and therefore you pay for the coolness factor to the tune of about $100 more. :)
 

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Don't worry about it, no sense knowing about a manifold nobody should ever buy 🤣
 

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Discussion Starter #31
Macstang, I've got headers and i can do a basic port and polish job on a set of heads but i'm in a crunch time wise. I hope to stay as close to plug-N-play as possible and develop some forward momentum on this car. It's been low on my priority list for too long.

Alan, I think/hope the compression will be ok with the domed pistons. The only thing I know about the cam is that it has a choppy idle from the previous owner.

xj222, Lets talk about that manifold.

my289, You are right about the manifold height. The difference is between the performer and the Performer RPM/air gap.
The previous owner of this engine had a C4 with a high stall converter. He blew that transmission and installed an AOD trans. His issue was with shifting from park to drive with a stock converter and a high idle speed.

1ofAMillion, That's a great idea about the dial indicator! I do have concerns about the cam. If it has decent street manners, I'll be happy.

jdub, I think the Performer RPM or Holly Street Dominator would be a good fit for this engine. Nice engine bay you have there.

BlakeTX, I haven't seen a good comparison in intake charge temps between the RPM and the RPM air gap. The air gap looks cooler, but aluminum may be too good of a heat conductor for it to make a difference.

67Modcoupe, you are correct on the height differences. I finally got a Motor Trend subscription last week!

jdub, I was going to try to keep the engine looking like a stock 289, but that would leave too much horse power on the table.

MrFlash, Checking the cam and degreeind it would be the right thing to do, but I fear one thing will lead to another and I hope to stay as close to plug-N-play as possible.

Rad, You read my mind, "get that thing going and see how it runs".

Thanks for the replies. I often see the question "what do you plan to do with the car" asked when a member is asking about parts. I plan to lay rubber every time the key is turned and find an autocross race and enjoy.
The one component I forgot to mention is the distributor. I want to take this engine back to a points distributor and have a knowledgeable pro set the ignition curve up.
 
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