Assuming he bored the block .020" over standard, a .25 CR increase would require close to .010" combined total removed from the deck and heads. The factory limit is a total of .008" combined total.

If he took everything off of the head, or everything off the decks (unlikely), the resulting CR #s might be different - one from the other - since I suspect (but haven't calculated) a combustion chamber reduction from head resurfacing has a different rate of CR change than a deck reduction.

Can you get the machine shop to tell you how much they removed from deck and heads?

Did anyone check the head thickness to see if they had been previously resurfaced?

Were any measurements taken of piston/deck clearance or head thickness before/during assembly?

Standard head thickness is 3.310" with a limit of -.008".... and although the deck clearance isn't a factory published number that I've seen, I've found it to be around -.015" IIRC.

Frank

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