Look at a detail of the rear oiling routing above:
Oil comes up from the pump through the rear main cap to the vertical passage.
First routing is the diagonal low in block...right and down to the rear main, left to feed the filter.
Oil is stopped from going higher by the little cup plug that is indicated here by an arrow, forcing it into filter and to the bearing also.
From the filter it feeds out the middle and back over to the vertical passage above that plug and goes on up to meet the main gallery and the side galleries for valve system.
Rear main gets its oil right before the filter. This is well documented in the soup your Chevy books and can of course be checked out visually on a bare block.
In Smokey Yunick's book, I think the "Power Secrets" one, he discusses this at length...he describes a couple of ways to get full filtering, then concludes that there is no prob with the stock setup anfd trying to modify it is a waste of time.
Picture shown is an '86 up type block, but oiling routes weren't changed.
Picture stolen from:
http://www.chevytalk.org/fusionbb/sh...hp?tid/192284/
