New TV - '85 Chevy Van - Quadrajet Question

[asps400]

I am fixing up a new TV. I just got a 1985 Chevy van with a 350 and a Quadrajet. I got a reman carb for $450 but it came with a different gasket. Besides the obvious, what is the difference between these two Gaskets? What will be the effect of using the new purple gasket?

[dadstoy]

I just replaced the Quadrajet on my Motorhome with Chevy 454. The rebuild came with that same open gasket. It works well and engine runs great!

[overlander64]

I am not certain when looking at your photos, but am wondering if you have something similar to what I have on my 500 cubic inch Eldorado. It has a black plastic insulator that looks very similar to the item in your photo -- there is a gasket installed above and below the insulator which is supposed to help reduce problems with vapor lock in hot weather. When installing my remanufactured quadrajet, the original had cork gaskets on either side of the insulator.

I am not certain whether this would apply to your motorhome, but thought that I might mention the possibility.

Kevin

[dadstoy]

There sure is a variety of base gaskets for the Q-Jet...

Gaskets - Base Gaskets - Quadrajet Carburetor, Rochester 2G Rebuilding & Tuning Parts & Tools

This link explains the thicker insulator gasket...

1/4" Thick Insulating Quadrajet Base Gasket Rochester Carburetor Parts

"1/4" thick gasket helps insulate carburetor from intake manifold heat and raises the carburetor to increase plenum volume. Raises the huge secondary throttle plates, relieving upper plenum restriction at full throttle, when used on a dual plane intake manifold."

I would try to determine which one was the original OEM and stick with that.

[dadstoy]

you should probably go with what ever is required for the plenum type of manifold you have...open or dual plane, etc.

see this link for explanation of different plenum manifolds.

Chevrolet Small Block V-8 ... - Google Books

[dadstoy]

...and of course this has me thinking about which one "should" be used on my 454. I don't remember which plenum type I have. I hate it when I start thinking!