Square bore vs. Quadrajet (spread bore)?

[Bundy]

I know that square bore has about the same size primary and secondary venturis whereas the speadbore/quadrajet have smaller primaries and larger secondaries. Can you run a speadbore on a squarebore manifold without an adapter? I ask because in trying to figure out my vacuum leak, I sprayed starter fluid around the base of the carb and the rpms picked up and in removing the carb I am wondering if I have the correct carb/intake.

My carb is a Carter 9605S Comp Series, which from what I read online is the similar to an Edelbrock 1407. I also have an edelbrock performer intake.

The carter carb is a quadrajet, right? Is my intake correct for a spreadbore??

 

[cs_88]

The base of that carb looks very similar to a Performer carb to me.
I have wondered before about the proper sealing of Performer carbs because of the two recesses on each side of the base. Those recesses are right where the base should seal against the intake.

 

[mcdobson]

Those are both "square bore" parts. The 1407 Edelbrock carb is based on an AFB style Carter (square bore). There is a real thin steel adapter for some square bores to some manifolds to cover any vacuum leaks. Look in Holley, trans-dapt, etc.. they all have them.

http://www.summitracing.com/parts/SUM-G1420/

 

[Bundy]

Those are both "square bore" parts. The 1407 Edelbrock carb is based on an AFB style Carter (square bore). There is a real thin steel adapter for some square bores to some manifolds to cover any vacuum leaks. Look in Holley, trans-dapt, etc.. they all have them.

http://www.summitracing.com/parts/SUM-G1420/

I see what you are talking about, but I didn't have an adapter before and it was running well. My intake looks like a square bore so maybe the gasket I used was bad or something?

 

[72Sport]

You might have a intake to head leak. I have had problems twice. Once I was sold the wrong gaskets and the second time the recommend gasket by Edelbrock leaked (old catalog. They now recommend different one, Edelbrock 7220. If I have another problem I am going back to stock Felpro and ignore the Edelbrock instructions.

Look at the top of the intake gaskets above the manifold runners. If they are not straight and you can see a crack in the top of the gasket that is where your problem is. If the cracks are big enough you will start using oil. You don't need to take it apart to see the top of a crack. It will be obvious after you start looking, I hope.

 

[mcdobson]

If it ran well before, just put a new gasket on and go.

 

[broncnaz]

New gasket maybe even double up or get one of the 1/4" thick gaskets just carefully torque the carb so you dont warp or crack the base.
Your carb is not considered a spread bore carb and its not a qjunk. Spread bore carbs have very small primaries and very large secondaries and in most cases they will not fit on square bore manifolds without a adapter due to the large secondaries I also believe the bolt pattern is different.