"I had a positive deck of .002-.004 w/the Felpro HP head gasket 4.125" bore. I did run 91 octane w/no detonation. (More info if needed)"
How, pray tell, did you achieve a 4.125" bore?????
That is the bore size of the Felpro head gasket.
I do not like that the headgasket has such a large bore, but @ the time it was the only high performance head gasket available.
MBHD
