If the manufacturer says it's .039" they probably know. If they are wrong and it's .002" thicker....I don't think the sky will come falling down.
No I don't think so either. Just trying to strike a balance between taking advantage of quench with a number in the .040" to .050" range and not worrying about having my heavy 2355 "6 pack" pistons hit my heads. So far I've taken some preliminary measurements and gotten .006" below deck on cylinder 1 and .003" below deck on cylinder 6. So if the Fel Pro 8519s really measure between .041" to .044" compressed it would work out well for what I'm doing.
