You wont have to worry about the crank as much as a connecting Rod going on Vacation out of the left or right sides of the block.
at .003 what kind of oil pressure should i expect at idle? what about rod clearances? and what should i tell the machinist about using pontiac rod? about widening it to fit. or should he know? if he doesnt pack up and go somewhere else or is widening a simple task?
I wouldn't think going .003 would be a good idea!? You will blead of all of the oil at the mains then, not enough oil to get pushed to the the rods and starve.
run it loose like jim said .003 mains or it will grab a bearing if in the budget get the shells coated and you could tighten it up to .0027
Clevite says for MOST APPLICATIONS you want 0.00075 to 0.0010 for every inch of shaft diameter. That means our "lamp post" 3.25" main journal on the conservative tight side would be 0.00075 x 3.25 = .0024 to 0.0032. They go on to say for high performance applications you should add 0.0005 to that. Now were talking 0.0029 to 0.0037. They go on to say that its a guide and application will determine the clearance, but I think the mains bleeding out is a bit of an exaggeration. Looser is better than tighter for a race app. Lots of good info here; http://www.clevite.com/techbulletins/CL77-1-205R.pdf
