I have a question for you, do you plan on adding water passaged on the deck? On my aluminum block we added the two water passaged right below the center exhaust ports. I also had problems with the 1/4-20 oil crossing holes in the front china wall leaking oil, we tapped them 1/16 NPT. Also one of the rear oil drain back hole is mostly covered by oil pan rail and gasket.
Lawndart,
I'm not going to add water holes to the deck.
I have not pressurized the oiling system yet so I'm not sure about the cross holes.
As far as the oil pan rail covering the rear return please see the picture in the beginning of the post.
Picture #3
