If the block has ever been line-bored, the crank and cam will move closer together by a few thousandths. There used to be engine rebuilders' timing gears (and chains)made to compensate for line boring, but I doubt that they would still be available now.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!