ub2693v

Recently i have had running issue with my 55, actually almost from the beginning, i could never get the idle to where I was satisfied, long story short, the cast iron throttle body was causing a vacuum leak, i swapped it out with an old carb I had sitting around (just the base) and now it runs perfect. Are these prone to warping/cracking? I thought it was due to the sloppiness of the shaft for the butterflies but both bases have about the same sloppiness.

As for the carb to the intake manifold, I have what was originally on the car which is a thick (maybe 1/2") gasket which has probably past its useful life or the single layer gasket that comes with a carb kit, does it matter or should I go with the thicker one? Right now I have the thinner one and it runs perfect but would the thicker one help keep the carburetor cooler being away from the manifold heat in stop/go traffic?

Its a 700700 according to the tag.

Wally

My guess, and it's only guess, is someone added the thick gasket to prevent vapor lock. If you have issues starting when it's already warmed up it may be vapor lock and you will need to add an insulating spacer.
There is one other thing you can do. If you pull the intake manifold you can block off the exhaust crossover to reduce the heat put into the carburetor.
Just my thoughts on the subject.
Wally

Olds64

Don't remove the intake manifold to block the exhaust crossover. The only engine that's going to gain HP by blocking the exhaust crossover is if you are racing.

You mentioned you had various carburetor gaskets from a kit. Did you rebuild the carburetor? Most drivability problems on an old carbureted engine can be tied to the condition of your carburetor or the setting of your timing/dwell (i.e. your tune-up settings).

justacog

The thick gasket is the OEM gasket on my 4GC in my '54 Super 88. I don't know why GM used a thick gasket rather than a thin one, but replacing it with a thin one would cause the choke heat pipe connection to not line up. It's that solid short hard line going from the manifold to the choke bi-metallic spring compartment.

ub2693v

The carburetor is fully cleaned and rebuilt, the car now runs perfect, i do see that the carburetor base gasket that is sold through Fusick is much thicker than the one available in the carburetor kits. I don't have any issues with vapor lock or anything, was just curious if anyone else had ever had issues with the cast iron throttle plate getting warped/cracked.

Tedd Thompson

I don't know how hot of an area you live in, but with a thin gasket and alcohol based 87 octane, I often had vapor lock issues on very hot days. When I replaced the gasket with a fiber thick gasket helped a lot, still not perfect on those 110 degrees days. Never had any problems with my throttle plate... Tedd

ub2693v

I live in northern NY, it doesn't get much higher than 90 or so in the summer and i run non-ethanol fuel anyway so vapor lock shouldn't be an issue, I did order the correct gasket from Fusick and hopefully that will be the last time I remove the carburetor for a while!!

DFitz

Yes, the thick gasket is the proper gasket. And yes, it is used to isolate the carb from the heat generated by the engine. It won't make a difference 90% of the time, but when it vapor locks, you'll be wishing you weren't in that 10%.

It doesn't hurt anything to use the thicker gasket.