Most everything has been mentioned but, there are still more. Tom mentioned about not having to pull the dist to do an intake swap but, it is even better than that. You can pull both heads, change rod bearings or more and not have to touch the dist/mag. Having the starter on the left has proven to be an advantage as some chebs have switched to a left side starter for an oil pan kickout on the right side. What about the rocker baffles? I have seen them in the Bill Mitchell catalog for chebs as a "new idea"!.
I like the motor mounts, the Pontiacs have the nut welded on, the cheb guys have the fuel pump in the way and have to hold a nut while they turn the bolt. There are so many little things like that that make a Pontiac more pleasurable to work on.
As to Pontiac engine production and the corporate thing. Believe it or not, it actually started in 1959! That is the last year that GMC trucks with the V-8 option used Pontiac power. I read that, though GMC customers were happy with Pontiac touque under their truck hoods, the Pontiac engine plant wasn't able to keep up with production for both cars and trucks so they dropped GMC and let cheb use their V-8s. Imagine how many HD 4bolt truck blocks and forged cranks and rods there would be today if Pontiac still supplied engines for GMC!
Steve
www.pontiacheaven.org