this was a polished, undercut radius standard 340 crankshaft with new standard MS 540 Clevite bearings right ? plastiguaged at .0025 clearance ? was this Assembly balanced ? Make sure the bearings weren't MS 540H champhered bearings, those are for the race cranks with full radiused fillets on the crank journals, and the rod journals. Bad news on a production crank. Just saying... also, if it was only hand polished with 600 grit paper, the crank may have even been eccentric or even bent at the #4 main.