Hi: currently running an edelbrock performer rpm intake on my '71 350. i have the eddie perf rpm camshaft in there now and yes its way to large for the streetable and daily driver application i want that has lots of low end torque. i'm switching to a much milder duration camshaft next spring (either comp cams or lunati voodoo). should i keep that eddie rpm intake or go back to my stock, cast iron one? compression is 8.5:1, running hooker long tubes and flow master delta flow 50's. have the option of either an edelbrock 600 cfm carb or my stock Qjet, i believe its 750 cfm. i have not touched the stock heads but might pull them to clean them up a bit.

 

You can pick-up the power by just changing heads, and maybe advancing the cam.
You don't mention the rear gear - under 3 doesn't help a large cam, and a 2000 + torque convertor would help a bunch, too!!

 

What exactly would he change the heads to? He could mill the heads and raise Cr up a point where the cam would work better. I had that cam (214/224) in a 9 to 1 355 with mildly ported heads and ran 14.8s. Switched to a 210/216 Engle, ran 14.2, eventually 13.9.

 

I always liked the RPM intake myself.

 

gears are probably 2.7? or even as low as 2.5?, not really sure. yeah that came with those gears and heads was a waste of money, fell head first into that classic trap of "bigger is better". i've been doing my homework now and pretty sure i want to go with either comp or lunati's 256 duration, both of which are supposed to work with my stock converter. going to keep stock heads and gears. i just put a shift kit in and that got some of the low end performance back but only marginally. i'm learing of porting those heads, don;t want to remove any metal,just want to clean them up a bit. car is just used for daily driving or good runs out in the country, no racing at all. fuel economy went in the toilet when i put that edelbrock cam in.

 

I have posted this a bunch of times,
http://www.realoldspower.com/phpBB2/...=performer+rpm
That same 9 to 1 355 was MUCH more responsive with the Performer and just a tad quicker.

 

I agree with captjim. With 8.5 you need a smaller cam. Your current and future combo doesnt jive.
Jmo

 

oh it definitely ain't jivin,that's for sure.

 

thanks for that article,captjim. good reading. i'll try my new cam with the rpm manifold first and if i get a chance might put the stock one back on just to see. reason i'm asking is i thought the rpm was made to function at high rpm it might negate the low end torque i'll be getting with my new cam choice. it looks cool though so i definitely want to keep it if i can.

 

Hey guys, just to update you. confirmed that the motor i have in my 71 is not original. it has #8 heads and the 73-6 intake. kind of bummed. Already got a line on some 7a heads, no idea what shape they're in. my new question, is there any performance difference between the 411880 intake and the ones originally put on a 71? still debating on whether to keep my RPM on or swap it out for the original seeing as i'm going with a milder cam and shooting for streetability and better mpg.

 

let me know if you want to get rid of the rpm manifold.

 

This actaully might not be a bad thing. If it is a 73 engine, it will have 14cc dish pistons vs 23 cc on the 71-72. Olds went back to a smaller dish with larger chamber in 73. So, get some early heads, mill a tad, good valve job, .028 gaskets, you are close to 9 to 1. Now you can run a little cam with the RPM and have a fun driver. Or don't mill, end up at 8.5, use a mild cam with stock intake and Q-jet. Or, mill the heads a bunch and bump Cr up tom 9.5 to 1. Of course this assumes the bottom end and rings are in good shape. The big disges in the 71-72 350s are killers, no way to work around them.

 

okay, cool. something to think about. many thanks.

 

update and a question. got the 7a heads and have had them cleaned up and a bit of porting done. question - are they identifical and interchangeable, can they gone on either side of the engine or is there a difference and one must go one one side and the other on the other side. If so how can you tell them apart? Putting them on this weekend, the #8's have already been removed.

 

Olds heads are ambidextrous. Fit either side. Normally the head with the stamping on the pad is the passenger side but it doesn't really matter.

 

thanks for the info. the head swap went well. car has more power now and runs smoother and sounds meaner.