Head gasket for a 65 401

[TurboKen]

What is the correct thickness headgasket for a stock 65 gs 401. Also what was the .015 head gasket and the .045 head gaskets application? What aftermarket headgaskets are people using today? thanks for your help,
Ken

[Dr. Frankenbuick]

Ken,

The 401 came with the steel shim gaskets. They run from 15-20 thousandths. Composite gaskets are available from a number of sources and have a compressed height of 35-40 thousandths. Using the composite gaskets will shave about .5 from the compression ratio, and brings the ratio down to around 9.75 to one.


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Steve B.
GSCA #2173 (1986)
67 GS 525 Stg IV
66 GS Convertible
65 GS HT
63 Riv

[TurboKen]

I have a set of the nos .045 steel gaskets. What was there appl. for, and was it to lower the compression for less detonation in racing? What benefits does the nailhead have in the lower compression? thanks,
Ken

[Dr. Frankenbuick]

Ken,

I'm not sure on those gaskets. I have not seen one that thick. They could be for heads or blocks that have been decked in order to maintain better geometry and compression. Or, maybe they are used to decrease compression so it will run on cheaper gas with less octane. I run 93 octane in my 66 without pinging. Much less and it rattles when on the throttle hard. It sure would be nice to pay a little less at the pump.

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Steve B.
GSCA #2173 (1986)
67 GS 525 Stg IV
66 GS Convertible
65 GS HT
63 Riv

[TurboKen]

The .045 gaskets came in a cylinder head overhaul kit.This was back in 65, you could order either the .015 or the .045 set.Thanks for your help,
Ken