All you do is match the bore in the mains to those in the bearing. I did it when i built the motor for Davids Del sol. So the support part of it is a mute point.
This is from
www.Theoldone.com
I catch a lot of flack about the size I open the oil holes in the bearings out to. Those who don't care for the practice, have never apparently experienced oiling problems, or they've never made enough power to be concerned. We open the oil holes in the bearings, after fitting the bearings to the block/crank with micrometers / dial-bore gauges and finally Plasti-Gage.) The holes are in perfect alignment with the feed holes in the main caps...and oddly enough, they're darned near the same diameter as the oil holes in the crankshaft. Who'd have thought? Also of note, we grind the edges of the girdle to remove any radius. That might sound strange, but sharp edges will "shave" oil off the rotating crankshaft and rod assembly with considerable efficiency and that's very desirable for a performance engine. It's also free, if you have a little time to spend.
Last edited by HatchVX; May 7, 2009 at 06:29 AM.