In the JG there is no info on the type or material makeup and thickness size of the insulator between the caburetor and the intake manifold for the Holley equipped Corvettes for 1970, specifically for the LT1.Please can someone clarify.
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Re: 1970 LT1 Holley Carburetor Insulator
Greg,
As you haven't gotten a reply yet I'll tell you what I remember from about 30 years ago and maybe someone else can confirm if I'm right or wrong. I purchased used a 70 LT-1 that was 2 years old and had 18,000 miles so I kind of think that he carb had never been removed. Later on when I took it off to replace leaking gaskets as I recall between the carb and intake was just what I refer to as a thermal gasket. Probably 1/8 inch thick, pressed paper like material on both sides of a thin metalic material I would guess to give some insulation.
Wayne -
Re: 1970 LT1 Holley Carburetor Insulator
Wayne and Greg------
I'm out of town currently and I'm just "peeking in", But, I'll see if I can deal with this one. For 1970 Corvettes, the carb gasket was about as Wayne described. However, all California Corvettes got a thicker insulating gasket as part of the EEC system. This insulator was used ONLY for California Corvettes. It's discontinued but available in reproduction from Dr. Rebuild.In Appreciation of John HinckleyComment
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Re: 1970 LT1 Holley Carburetor Insulator
Wayne and Joe,
The LT1 is a Canadian car,delivered to a Chevy dealer in Toronto.It does not have the EEC system.Does the metalic insulator extend beyond the intake manifold and does it display a part number,and is it the baffle type? I received other information that the thickness might be 1/4 inch.Please explain.
GregComment
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Re: 1970 LT1 Holley Carburetor Insulator
Greg,
Just because the car was not sold new in California does not mean that it did not have the NA9 option that included Evaporative Emissions Control. About half of the NA9 equipped cars I have seen were originally delivered in states other than California, but I must add that if I resided in California I am sure those numbers would be different.
No, the aluminum shield Joe refers to does not extend beyond the intake manifold, if falls short of the valve covers by an inch or two. I do not believe that it is as thick as one quarter inch either. Several years ago it was still available from Chevrolet in the Performance Parts Catalog, but I am not up to the moment on availability.TerryComment
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Re: 1970 LT1 Holley Carburetor Insulator
Terry,
The NA9 option was not written on the original bill of sale from the dealer,nor on the GM of Canada's build sheet,which would be same as the tank sticker.This is an early Jauary car.Where else would the NA9 option have been written.
Without the NA9 option the material is less than 1/4 inch and is aluminum.
GregComment
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TerryComment
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Re: NA9 option
Terry,
Thanks for the explanation to this option.In my discussion with the 2 car owners before me,the car never had a frame off.There is no evidence of the hardware associated with the NA9 option.The original GM insulator is essentially dark brown fiber material,3/16th thick with no evidence of metalic material?
GregComment
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1970 LT1 carburetor insulator
Greg...
I went to the garage and looked. 1/8 inch is probably more accurate, but it is impossible to measure it on the car. Mine looks black, but after more than 30 years it might be just dirty on the edges or discolored from fuel. There is no sign of metal that one can see with it installed.TerryComment
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Re: 1970 LT1 carburetor insulator
Terry,
Thank you for all your help.I now know what to look for to make the correct purchase.
GregComment
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