what about #5,6,7,8?
does the psi go up on the rear cylinders?
as in maybe the decks are off on the block/heads?
leakdown test.
if you are determined to pull heads off, just pull one and see if the flame ring has been pushed out, if not..I wouldn't pull the other head....but I would cc the head thats off as would I check the how much the valve job was sunk or stems cut.
look at the keeper/lock grooves to see if some are lower/higher than others.
