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Discussion Starter #1
I bought a used engine, minus the intake and carb. It's a 302 with 351W heads. Any thoughts about how a Performer RPM intake would compare to a stock 289 4bbl intake?
 

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There are any number of intake "shootouts" one internet that have dyno comparisons. It will provide significant improvement as long as you improve the flow on the exhaust side with headers. Look at it this way, Shelby added 35 HP to the 289HP by changing to a similar intake, headers and different carb.
 

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Discussion Starter #3
Thanks for the reply 66.
I initially planned to dress the engine as a stock looking 289, but that's going to leave too much horsepower be on table.
The RPM air gap manifold seems like it would have hood clearance issues in a 65 so the Performer RPM looks like the best choice.
 

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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.

764416
 

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I would not hesitate to use a Perf RPM.
What about camshaft?
Now would be the perfect time to swap in a better cam.
 

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I would not hesitate to use a Perf RPM.
What about camshaft?
Now would be the perfect time to swap in a better cam.
That's true. Compatibility is important for performance. A Performer RPM manifold would be wasted on a C3AZ-V cam.
 

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The performer RPM is a good intake. I run on my 68, 302, with a Holley 670 SA on top. Response is good on the throttle. I also have a upgraded cam as well, so that helps. I would say you cannot go wrong with one.

My 65 has a wieland stealth intake, which is also good combo, but I am running a 351w in it, with stage 2 cams and twisted heads.
 

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Discussion Starter #8
OK, this is where I get to sound like a dummy.
The reason I was able to buy this engine at a bargain price is that the 2nd owner didn't know what was in the engine. All he knew was that it had too much cam for the AOD transmission he had switched to. So all I know from him is that it has a "big" cam and low miles.
Looking it over I've found DOOE heads, Harland Sharp roller rockers, pop up pistons with valve reliefs cut into the tops and the bearings look great.
 

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Discussion Starter #9
Let me ask about a few other items.
I need a clutch, planning on buying a Mcleod 10/1/2" up to 400 hp clutch.
Gaskets: oil pan, intake and rear main seal. For the intake I'll use 1.2" X 2" Fel Pros.
I'm undecided about the rear main and oil pan. They seem to range in price by a wide margin.

I could use some advice as to what works best on the rear main and oil pan.
 

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Headers will do more by themselves than just the RPM intake. The engine is already constricted also by the heads and cam depending on what cam it is. It won't hurt anything to get one but you leave a lot of the benefits of it on the table if you don't address the heads and cam also. I don't think that the original iron 4 barrel intake by itself is much of a problem. Scott Drake sells a reproduction 4 hole Cobra intake but it is a bit pricey compared to some of the other options available.
 

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The chart posted above appears to have a edelbrock performer. The performer RPM flows way better. Stock 351w heads don't flow very well compared to today's aftermarket heads. My humble opinion is without knowing the head flow, compression ratio and cam, its hard to estimate the performance of this engine.
 

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It looks like the Holley Street Dominator does really well. I just so happen to have a used one for sale...
 

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I believe the Performer RPM and Air Gap are the same height. Not using the AOD because of an engine does not make sense as the AOD does not use Vacuum signal as a C4/C6 trans, it uses a TV (throttle valve) cable to know where the engine is for shifting, but doesn't seem to matter as you are using a manual trans now.
 

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What an interesting predicament. Sound like good stuff but what was it built to do?
I would invest in a dial indicator and start measuring lift and other stuff. You may want to actually use a smaller cam depending on your car.You might pop off a head and try to figure the comp ratio or you're just guessing and could easily have a bad combo in the end.
But ya, almost any intake would be better.
 

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Try a Weiand Street Warrior if you feel the Performer RPM or Stealth will be too aggressive for your needs. It sure is priced right at about $85 cheaper than the Performer RPM. My friend put one his otherwise stock C-Code with a Summit 500cfm carb and it's working great. I watched an episode of Hot Rod Garage where they ran mid 12s on the Street Warrior in a 1985 5.0, so it can perform too if needed.

The RPM air gap manifold seems like it would have hood clearance issues in a 65 so the Performer RPM looks like the best choice.
I have the AirGap with a 1" spacer and the TCP engine mounts that raise the engine up 0.5" and there were no clearance issues with a drop base and 2.5" filter. Looks like this:

764433
 

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Here's my understanding of things.

Performer - similar to old Cobra aluminum intake. It's fine.
Performer RPM - considerably better than the regular performer.
Performer RPM AirGap - very similar in performance to the RPM, though it theoretically might run cooler since there's some separation (air) between the runners and the valley. I do think it looks really cool though.

There should be no clearance issues with any of them. I have no personal experience with Weiand, but I've heard good things.
 

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The RPM and Air Gap have the same carb pad height (4.90" for the 302 version). The Performer is 4.12". I run an air gap on my roller cam 302 and it fits below the stock hood on a 1967 coupe. Motor Trend TV did a shootout of a few different intakes. I forget the spec but I believe it was 351 based. Here's how they stack ranked.
 

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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.
 
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