head gasket thickness:

[zlfanatic]

What is the correct head gasket thickness for me 68 Newport 383,some are .012-.019 while others say .032-.042.If it came originally with the thinner gasket and the thicker one was installed would'nt that lower my CR.

[John Kunkel]

All big block Mopars came from the factory with a steel shim head gasket in the .019"-.022" range, any gaskets thicker than that are aftermarket and, yes, the thicker gasket will lower the CR.

[amxauto-x]

If it came originally with the thinner gasket and the thicker one was installed would'nt that lower my CR.

Yes it would. What are you doing with it? Stock? Just driving around? Is it rebuilt? What compression ratio does it have now?

[zlfanatic]

Thanks for the replies,my question is, should I change back to the thinner gasket or keep the thicker one.It's a stock engine,would it make that much of a difference.

[6 packin]

I m tring to think what the compression ratio is on the 68 383 engines......hmm? The felpro Blue Prema Torques cost near $30 a piece, thats 60 a set, and is a .039 compressed thickness. The steel shim gaskets P4286754 have a compressed thickness of .020 or so, and cost only $22 a set. Your drop in compression by going to the felpro's may be a good thing on early engines. The gas has changed alot since then. I doubt you could tell much diff in a stock engine. If you do use the steel ones, pick up some copper sray gasket, give them a good coat. They tend to seep water somtimes.

[zlfanatic]

The stock CR was 9.2-1,that was with the steel gasket,curios what it would be with the thicker gasket.

[6 packin]

Real close to 9:1 so you will loose around 1/4 point on a 440 engine, yours will be slightly less than that.

[72Challenger]

Going from a .020 gasket on a 9.2:1 compression 383 to a .039 gasket would drop the CR to 8.84:1.