Well, my first v8 swap happened to be very interesting. Basically, i got a non running 88 rs with the 305tbi. I also had an unknown sbc that was going in. Long story short, i learned a lot about cams, timing, intakes, exhaust, fuel systems, and carburetors. After many months of tweaking and wondering why it wasn't running right i finally found out all the specs to the motor.

3970010 block w/327 large journal forged crank, speedpro forged dome top pistons, 462 camel hump heads, ported w/ 2.02/1.60 stainless, weiand single plane with 3/4" raised plenum, 650 holley dp, t-5 w/ 4.10's. Cam is a crane cams mechanical flat tappet #111411 292/300 adv. dur, 256/264 dur @ .050, .545/.563 lift, 105 LSA.

I removed the ecu, wires, sensors, a/c condenser. I put in an all new fuel system and dual 2.5" exhuast w/ headers, magnaflow mufflers and no cats.

I've had a hell of a time getting it to idle right, and to be street friendly. freaking hell.

Which brings us to my main question: What difference will i see switching to an Edelbrock Performer RPM Air Gap?? A bunch of forums say that it is good for all around power, but how will it do with a cam who's operating power band is 4200-7200??? And how about a top end?? i have become quite used to taking it to 7000rpm just because it sounds good and it has ridiculous power.

-Josh

 

Welcome to the forums.

I checked Edelbrock's website, it says that the Performer RPM Air Gap is supposed to make power between 1500-6500 rpm, however iirc from people writing in to chevy magazines I read, those ratings are for a 350 c.i.d. engine (someone chime in if I'm wrong). If I'm correct that intake should probably rev to 7000 when installed on your 327.

 

The Performer RPM's powerband is a function of the runner length, so being on a smaller engine won't make it rev any higher (unlike a camshaft - but even then, it wouldn't be a 500 RPM difference, maybe 100 RPMs).

Bottom line is there isn't an intake out there that will make that engine street-friendly. The cam is the reason for that. Not that you couldn't drive it on the street, but the power will always come in at a high RPM.

A Victor Jr. is the right intake for that cam. If you want it to be more street friendly, put in a smaller cam and then install the Performer RPM.

 

The current intake i have is a weiand single plane, but just not with the space underneath (like the victor jr.). I was looking at the rpm air gap so i could increase manifold vacuum at idle by a little.

 

If i change to the performer rpm air gap, will i need to re-jet my carb? It is currently a holley 650dp #4777-c, jetted 70-70, w/#28 shooters(but really sould be #35).

Is there a general rule from going from a single plane to a dual plane??

Advice much appreciated!

thanks, Josh

 

I wouldn't say there is a general rule, but plan on adjustments and possible rejetting.

The dual plane intake won't have a significant effect on your idle vacuum. It's the cam that is causing low idle vacuum, not the intake.

The carb is jetted 70/70? Does that mean no primary power valve, or both primary and secondary power valve? Either way, it doesn't sound right. You shouldn't need 35 squirters, either.

 

yup, 70-70 with a 2.0 power valve in the main system. I check my plugs quite often, and the have a nice tan color to them. With the #28 shooters, it would stumble of the line. i just got #35 shooters and a pump cam kit.

Wouldn't the performer rpm air gap add a little more low and mid range torque?