Greg you make no mention of what block this is (one you've been running?), mega, stocker? as others have mentioned studs can cause issues even if they're loose in the cap. 25 years ago i had a 340 that wouldn't even turn with studs. not knowing what to do or having the $$$ to hone it i put the bolts back in it. engine ran 11teens and is still together and running this day. just because the engine was correct before and ran OK doesn't mean things can't or won't move some. if you've measured the bores without bearings and are getting bad readings might be time to hone it. also remember even if the numbers are good doesn't mean the bores are in a straight line. the stock FM "book" spec for the bores is 2.9425-2.9430