Question: Correct Configuration for Spreadbore?

[Vette79]

I have the Edelbrock Performer RPM 7104 Intake Manifold, the Holley 108-118 base gasket, and the Holley 0-9895 carburetor. Will there be any need to increase primary jet size on carb with the upgrade of the intake from Performer to Performer RPM?


http://www.edelbrock.com/automotive/mc/manifolds/chevy/performer-rpm-sb.shtml

https://www.holley.com/products/fue...arburetors/emissions_replacement/parts/0-9895

https://www.holley.com/products/Fuel_Systems/Carburetor_Components/Gaskets/parts/108-118

 

[Peer81]

Only way to check this is with a A/F ratio meter or on a dyno. But i would say carbs always need to be tuned to the specs of your engine to get the best out of it.

Greetings Peter

 

[Hib Halverson]

Before you worry about jets, make sure 1) your engine can really use that intake manifold and 2) that it will fit under your hood.

Typically, Performer RPMs will not fit under a stock hood.

 

[KANE]

Before you worry about jets, make sure 1) your engine can really use that intake manifold and 2) that it will fit under your hood.

Typically, Performer RPMs will not fit under a stock hood.

Hib's right on with the fit... both under the hood and for the engine itself.

I have the Edelbrock Performer RPM 7104 Intake Manifold, the Holley 108-118 base gasket, and the Holley 0-9895 carburetor. Will there be any need to increase primary jet size on carb with the upgrade of the intake from Performer to Performer RPM?

So... what cam and heads are you running???

 

[kpic]

CHEVROLET 262-400 SMALL-BLOCK V8
PERFORMER RPM Q-JET (1500-6500 RPM)
Designed for 1955-86 262-400 c.i.d. Chevy V8's for spread-bore (Q-Jet) or square-bore carbs. Delivers maximum power and a broad torque curve for high-performance street. Carb pad will accept square-bore carbs without adapters. #2504 Marine intake features brass lined front water crossover and brass flange inserts to cover the rear water openings. Performer RPM Q-Jet has same provisions as #7101.Will not fit under stock Corvette hood.
Intake Manifolds - Chevy - Small-Block - Performer RPM Series - Edelbrock, LLC.

Vette79
As Hib advised and the text at the link provided stated: clearance problems.

Kane
As the basic Rochester family had 1-3/8" primaries and 2-1/4" secondaries, I believe the stock Rochester was a M4MC which had ~750 CFM. However, there are a lot of Rochester 4 barrel carburetors, so I could easily be wrong.

We used to add a notch to the GM "snowflake" manifolds.