While measuring main bearings, # 3 came out with serious differences between the front side of the bearing and the back side. All measurments done at 12 oclock/six oclock, 90 degrees to the parting line. Front side, .0025. Back side, .004! Pulled the cap off, looked it over for obvious things like debris under the cap, a nick on the cap or block. I took the studs out and ran a stone over the mating surfaces lightly to see if anything showed up. Nothing. There is no material from cap walk affecting it, looks good. I tried another bearing, same readings. I pulled the cap off, and reset the dial bore gauge to that diameter, and got the same thing, back side over .001 too big. Checking the main bore, it is as if the cap is cocked in the block, the measurements taper perfectly from one side to the other. It actually measured .0017 difference. I am stumped. All readings done with studs torqued to spec. Any ideas?