Choosing an Intake help

[NicoSlam]

What type of edelbrock intake is good for a standard 350 with q-jet? Someone locally is selling a Performer RPM (not airgap) for a good price but there are so many selections I need some first hand advice. thanks

[pumpkin]

As far as a manifold for a reasonably stock 350, there is not much of a power differance if any over the stock manifold. Chev did a great job when they built it. The only real reason to go with the aluminum manofold is for the looks, and they warm up a bit quicker, so cold start drivability can be improved somewhat. As far as I can remember the Performer RPM manifolds are square bolt carb mounting for Holley or AFB. If your engine operates like most under 4500 rpm you will not see any performance gains from a manifold with bigger passages.

[geezer#99]

Performer RPM has a square bore flange for the carb. You need a standard performer which is a spreadbore flange made for your quadrajet or you can use an adaptor on the RPM which is spreadbore to square bore.

['72customdeluxe]

There is a spread bore rpm available
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[RUSHNBOBO]

Originally Posted by '72customdeluxe

There is a spread bore rpm available
Posted via Mobile Device

If the rpm manifold does come in spreadbore configuration this is much more desirable than a adaptor ...these are proven power killers. Why?....its because of the drastic turn the air has to make directly after the carb to enter the manifold.

As to the difference to the performer vs. rpm performer....unless your engine is modified to optimize the larger plenum area of the rpm, ie. at least 9.5:1 compression 220 @.50 or more duration cam and long tube headers at least 1 5/8 dia. you may actually lose power with the rpm....its all about velocity.

Bigger area creates slower velocity and unless your motor is built up to use this larger area the slow velocity of air makes for a poor flow through the carb resulting in less power....more air and fuel in and more exhaust out = more power. But this is about flow more than size.

When u build a motor remember this rule >

A little to small is always better than a little to big!!!!!!!!!!!!!.......that goes for cam, carb cfm, primary tube,exhaust dia. head intake volume manifold and head port volume. .................hope this helps.............

[llowlife]

If you are running a stock motor with normal driving patterns. Save your money for something else. There is not enough to be gained unless you like the look of it. Also realize there are running revisions of intakes. The early performer was only a slight improvement over stock. The later versions had better flow distribution.

[NicoSlam]

Thanks everyone for your advice. I think I'll pass on the manifold as it needed an adapter for the Q-jet.

[Davetopay]

Just as an extra 2c....I have a 350 with the 041 heads, Vette casting #'s on the rams horns(if it means anything), a decent dual exhaust, and a cam of unknown origin. The original Performer and Q-jet combo is EXCELLENT with this very mild setup. I can pull the motor all the way down around 800rpm, and wind it all the way out to 5500, but don't need to. It really shines between 2000 and 4000 with no stutters, bogs, hesitation, or coughing. Also gets up to 15-16mpg on the highway.