RPM Air Gap
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 895
Likes: 4
From: whitman massachusetts
RPM Air Gap
I have an Edelbrock RPM Air Gap intake installed on my ZZ383. I am trying to figure the way to go for a carburetor, and decided to go with a rebuild on a Quadrajet, tuned in to my motors spec. I am just a bit confused on the Rochester being a spread-bore and the Air Gap intake being a square-bore. Will a Quadrajet work effeciently with this intake, or will I be sacraficing performance? Any info is appreciated.
Race Director
Joined: Jun 2000
Posts: 10,046
Likes: 675
From: FL
You will need an adapter to fit the spread bore Q-Jet on the square bore RPM Air Gap. That may disturb flow and will add height which may be an issue based on your hood. A more elegant solution is the 7104 RPM Q-Jet. It is not an Air Gap but does have the spread bore pattern so the Q-Jet fits nicely.
Here is mine using a Moroso Low Profile Racing Aircleaner with 14x3" filter. I did have to dimple the base a little for the accelerator pump arm. I have 3/4" clearance with the stock '75 hood.
Here is mine using a Moroso Low Profile Racing Aircleaner with 14x3" filter. I did have to dimple the base a little for the accelerator pump arm. I have 3/4" clearance with the stock '75 hood.
Last edited by SteveG75; Feb 28, 2009 at 10:21 PM.
Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
The RPM Air Gap is only for square bore. The regular Performer Air Gap comes in square or spread bore. I have heard that Lars says you should not use an air gap manifold on a street car, so if you are looking for performance in that RPM range, I would go with the regular RPM non-Air Gap manifold. If you already own the RPM Air Gap manifold, it is a high demand item that I'm sure you can sell for what either a Performer Air Gap or a regular RPM manifold would cost.
God bless, Sensei
God bless, Sensei
Pro
Joined: Mar 2008
Posts: 716
Likes: 1
From: Albuquerque New Mexico
The RPM Air Gap is only for square bore. The regular Performer Air Gap comes in square or spread bore. I have heard that Lars says you should not use an air gap manifold on a street car, so if you are looking for performance in that RPM range, I would go with the regular RPM non-Air Gap manifold. If you already own the RPM Air Gap manifold, it is a high demand item that I'm sure you can sell for what either a Performer Air Gap or a regular RPM manifold would cost.
God bless, Sensei
God bless, Sensei
Melting Slicks
Joined: May 2005
Posts: 2,209
Likes: 12
From: Montgomery Alabama
Cruise-In VII Veteran
St. Jude Donor '06
This post adds very little to this conversation
"I have heard that Lars says"
I read that someone heard that someone else said Lars said this too....
Personally, I wouldn't put a Q-Jet on an adapter to make it square bore to fit the air gap intake, but heck, it just might make more HP that way.
I bougth the air gap, and the Thunder Road series carb for it, then found out my L88 hood was a piece of crap, so it has been sitting in a box waiting on me to get a good L88 hood.
I read that someone heard that someone else said Lars said this too....
Personally, I wouldn't put a Q-Jet on an adapter to make it square bore to fit the air gap intake, but heck, it just might make more HP that way.
I bougth the air gap, and the Thunder Road series carb for it, then found out my L88 hood was a piece of crap, so it has been sitting in a box waiting on me to get a good L88 hood.
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Racer
Joined: Apr 2006
Posts: 477
Likes: 43
From: Millbrae California
The reason i avoid air-gap intakes for a non-race application is: The factory intake manifolds used heat from the exhaust crossover on the bottom of the intake manifold in an effort to help further vaporize the air/fuel mixture as it passed thru the intake manifold on its way to each cylinder of the engine. Many of the aftermarket high performance manifolds on the market today including air-gao intakes block this exhaust crossover in an effort to increase high rpm engine power. The lack of exhaust heat in this non-exhaust heated style of intake manifolds will often cause some engine driveability problems because some of the vaporized fuel will condense back into a liquid. An engine can only properly burn gasoline that is in a vaporized form evenly mixed with the air in its combustion chamber. The added high rpm performance that an non exhaust heated and/or air-gap intake manifold offers is often offset by a loss of driveability and power at lower rpm engine operating conditions.
I hope this helps Henry @ olescarb
I hope this helps Henry @ olescarb
