I finally went and got actual plugs for the oil drain backs. I was concerned about oil being trapped, and cooking/sludging, at the plugs so I took the tiniest drill bit I had and made a drain hole, then to promote sticking it to the wall of the block rather than drip onto the rotating assembly. I also numbered them to the corresponding cylinder to make it easy to re-install them after I remove them for the actual machine shop work.
I also drilled the first two holes in the block to re-route the return oil. The first one was a difficult angle to achieve (why the oem didn't do it!), but I finally got the drill bit to bite and have one re-routed internally to the oil fill cavity. So this one will drain back behind an oil baffle. I'll probably run that baffle a bit below the oil pan rail to be sure it clears the crank.
The last hole I drilled today, and tapped, was the first drain. There is a nice block in the casting where the passage changes direction so I centered up and drilled a 9/16th hole there and tapped it for a flared fitting. I will add a corresponding fitting in the oil fill area to drain too. It will likely "disappear" from sight when the fitting and line are painted Pontiac Blue.
I need to drill and tap one more return line for the rear most drain. That one is a bit more complicated due to the casting ribs from the bell housing, but should still be able to make it work.
