Could it be possible that you may have the wrong bearings? You may have bearings that are for a crank that has been machine turned which needs a thicker bearing. If your crank has not been turned and you have the thicker bearing, it would bind up.
Too much clearance!! The rear should be .002 to .003 at the most. Looking for an oil leak otherwise, not to mention oil pressure problems.
Mains .002 to .003 Minimum Preferred .005 to .007 end play
Rods .002 to .0025 Side clearance .010 to .020
You guys just can't catch a break..
I'll tighten up the rear main a bit to improve oil control at the rear main seal, IF I'm looking at a really long term engine. If it's one that's going to be run hard and rebuilt then .002 is best. But that's just me. I've seen lots of factory built engines with .0015 rear bearings.