David, that is not exactly apples to apples. A better example is your new, in spec engine has a total open clearance (not sure how you would measure such a thing) for discussions sake equivalent to a hole .2". If you push x gal/ hr through that hole, you will have y PSI of back pressure getting that much
oil through that hole. Now open that hole to .3". If you increase the flow to some x', you can achieve the same pressure, but at a higher flow rate. The pressure is what assures that
oil is getting everywhere. With some miniscule (maybe 2-5 PSI) you could maybe get some
oil to the first main bearing, but not stand a chance of it getting up the pushrods to the rockers. A larger swept volume oil pump will hold the same pressure with a larger clearance and/or lower viscosity oil. A larger volume oil pump will also spend more time bypassing excess flow
I checked and have the overall length correct. I also checked the block depth to see that yes, the gear should ride on the block. That's the only sensible way. There is no provision to lubricate the top of the distributor. Bronze bushings are OK to keep the rotor centered in the cap, but not take the downforce of the gear without oil flow.
It just gave me a oh no moment thinking you were saying the gear should never touch the block.