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This sbc engine had .001" undersize main bearing half shells in the caps with standard shells in the block when I got it. In the rebuilding process I had the crank polished. I installed standard main bearings upper and lower to check clearances. I come up with .0032-34" on #1 - #4 with #5 at .0044" with the oil pump torqued. I bought std's and .001's knowing this, so I have both on hand. This needs to go back the same way, I'd say, .001" lower and std upper for .0027"-29" clearances on #1-#4. Except I'm wondering if #5 should be tightened up with both .001" shells. In other words, would you run #5 at .0034" or .0039"?
Along with having the crank polished, I had the rods resized. So really starting at square one with them. The rod bearing clearances with std bearings is running .0035" to .0038". .001" undersize bearings gets me to .0025-28". That is just a tad looser than I would have liked, but I could live with it. There is a .002" undersize bearing that could be mixed, on 5 rods, with a .001" half shell to get them all to .0022-25". Would you stay at the .0025-28" or tighten it up to the .0022-.0025 range?
Is it correct that the undersize shell goes in the load side? Cap for mains and rod for rods?
Am I on the right track here?
Thanks guys.
 

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I'd go with the combination that gives the .0027-.0029" on the 1-4 mains and the .0034" on the rear main. On the rods the .0025-.0028" set-up.

I've seen some discussions about which side the put the undersize shell on, over at SpeedTalk opinion was that it doesn't really matter, use one half when you assemble it, and use the other halves for the refresh or a different build.

My opinion is that is doesn't matter either, clearance is clearance, the crank journal and oil film don't know which bearing is where, just how much total clearance there is.
 
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