Ok, I just rebuilt my 302 and had an oil pressure problem. So I tore it back apart and think my main bearings are suspect. Crank was ground .010 under to 2.240. Used clevite 77 "p" .010. I have a bit too much clearance between the crank and bearings. Plastigage says less than .003 clearance. Which makes sense because: the original bearings measure .096 thick, and the clevites measure .101. If they're supposed to be ".010" over, my math says they should be closer to .106? That would fit about perfect. I've tried two sets, both measure .101" I'm going to pull out the crank and re-check the crank bore in the block. I hope I don't find out of round mains. But either way, whats up with the bearings? they should be .010 over size, not .005 right? Anybody have any Ideas??? Thanks everybody!

 

The bearings are correct. When you grind a crank .010 under, only .005 is removed from each "side" of the journal. So the bearings are only .005 thicker.
When you say you have less that .003 bearing clearance, what type of plastigauge are you using? The bearing clearance should be around .001-.0025 clearance depending on how it was machined and how you are using the vehicle.

And you said you had a oil pressure problem, was it knocking? Did you use a mechanical gauge? What did you torque the mains to?

 

Maybe the cam bearings are misaligned. Isn't there an oil hole in the cam bearings so the oil can pass through?