Main bearings are precision fitted- - - -DO NOT do any scraping! Babbit connecting rods can be scrape-fitted and then shimmed for the proper clearance. Use shims between the main bearing caps and the engine block to get the proper clearance, usually between .001" and .003". "Less is better" as long as there's enough clearance for oil to get in there and lubricate the bearing. I prefer to use a narrow piece of shim stock between the bearing and the crankshaft instead of plastigauge. For instance, place a piece of .001" shim stock about 1/4" wide between the bearing and the crankshaft, and add shims between the cap and the block until the crankshaft can be turned with a moderate amount of drag. Then remove the checking shim and move on to the next bearing. Fit the bearings BEFORE installing the rope oil seal, as it will give you a false drag indication to deal with. The main bearing shim set that appears to be one thick piece is actually 5 thin layers glued together. Each layer is about .0005" thick. Use a razor blade or an X-Acto knife to peel individual layers apart.

After you make 2 or 3 more posts you will have access to the private message function of the site. Send me a PM once you're off "moderation" and we can discuss things in more detail by PM or phone. There are a few other very important assembly techniques for a Babbit connecting rod engine that MUST be followed to assure the engine survives the first startup after an overhaul. Good luck!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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