[Alan Roehrich]

Darren, no I have not taken a measurement. If the oil holes are properly chamfered, they really cannot catch on the parting line, as the bearing would have to move a ton in order to grab. Several of us have looked at this for years, and the best we can tell, the main saddle moves, and when it does, the bearing pinches the crank at the parting line. Usually, when it happens, it gets bad enough, fast enough, that it gives you false ideas about why it happens.

So long as your bearing bore is round, and the correct size, the crush is correct with the bearing at stock length, that is what gives the bearing proper eccentricity, while holding the bearing in place. If you shorten the bearing the way you are thinking, the bearing will lose crush, which will take away eccentricity, which in turn will do the opposite of what you are trying to do, instead of getting more clearance at the parting line, you'll have less. That problem will be compounded by a lack of crush to located the bearing, so it will try to move more.

At this point, I'd suggest you get a set of Federal Mogul 108M race bearings, finish the block (align hone) to minimum size, install the bearings, torque the caps (and any added hardware, girdle, etc) measure the bores, grind the crank to yield a minimum of 0.0035", and a maximum of 0.004" vertical oil clearance. I'd send the bearings, mains and rods (Clevite is fine for the rods), off to HM Elliott, and have them coat the bearings.

Also, I'd suggest you find someone that will let you sort through oil pumps. You need to find one with the least amount of clearance between the sides of the gears and the housing as possible, 0.003" would be ideal, but I'd bet you'll have a hard time getting under 0.005". When you get your pump picked out, then use either a machinist's stone, or a piece of sand paper on a piece of glass, to sand the housing so that with the gasket in place, you have about 0.002" end clearance in the pump. If you use a standard volume pump, with a stamped steel cover, get a second cover from an old pump, and install it as a support for the cover that came with the pump, you'll need to get correct length bolts.