by chiefss » Tue Jun 02, 2009 11:20 pm
They were all "hemi heads", as you put it. The gasket thickness will have minimum effect on the way the engine runs. They were mostly run on 5 to 10% nitro in the years they were used and if anything a thicker gasket might require a little more nitromethane. However I doubt you would notice any difference on any gasket material you might use. Just get the thinnest that will withstand higher temps and pressures. Paper gasket material won't work. I have made dozens of head gaskets for 60's vintage engines and never worried about thickness all that much.