Originally Posted by Bryce S.
(the bearing material is built directly into the pistons, correct?)

No, Babbit metal is in the big ends of the connecting rods instead of having an insert bearing there. Check the front main bearing for debris between the bearing and the block or the cap, and/or add another shim between the front main cap and the block to see if it frees up the crankshaft. There is a dowel built into the back of the upper main bearing shell that must align with a hole in the block, also.
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!