Ahh, that makes sense. The Pontiac V8s have a huge oil galley under the drilled rocker arm studs, so there's just all kinds of oil up top on those engines.

I have a booklet about that four, written by the guys who designed and built it, and presented at the Autorama in November 1960. It goes into some detail about how proud they were of the extensive ball and socket rocker arm lubrication setup they had made for Pontiac engines.

I could totally see why GMC used a variant of that V8 in their trucks. IMHO they should have continued with it versus the 366/427 industrial engines-every one of those I found in the salvage yards back in the '90s had spun bearings and other issues, yet were still ludicrously expensive because 'Big Block Chevy.' No small part of why I went to the Cadillac V8 with its burly bottom end. And yard full of free cores I had to hand.. :-D

1965 C60 school bus | 1967 GMC 6500 school bus