1970 LT-1 Base Carburetor Gasket

[George C.]

Did the 1970 LT-1s (non NA9) come from the factory with a 1/4 inch insulated base gasket under the Holley 4150 (list 4555) carburetor?

If so, where can you find that insulated base gasket. Additionally, the choke rod would need to be longer if you raised the carburetor.

I believe it would help me with hot restarts to put a insulted base gasket under the carburetor.

[Joe L.]

Re: 1970 LT-1 Base Carburetor Gasket

Did the 1970 LT-1s (non NA9) come from the factory with a 1/4 inch insulated base gasket under the Holley 4150 (list 4555) carburetor?

If so, where can you find that insulated base gasket. Additionally, the choke rod would need to be longer if you raised the carburetor.

I believe it would help me with hot restarts to put a insulted base gasket under the carburetor.

George------


No, 1970 LT-1 without EEC (NA-9) did not originally use a 1/4" thick insulating gasket. The 1970 LT-1 application used a simple, thin gasket with an open plenum. It was originally GM #3881847 and later GM #682914. An excellent reproduction is available from Dr. Rebuild.

If you wish to use a thick, insulating gasket you could use reproductions of the 71-72 LT-1 gasket or the 1970 with EEC gasket which includes an aluminum heat shield. Both are available from Dr. Rebuild. As you mention, though, if you change to the thicker gaskets you need to also change the auto choke rod.