If you really want to get down to the most detailed information regarding Pontiacs, I would recommend also joining the Performance Years forum. Like Lateral G, the guys there are also very helpful and would probably like to see your build as well. Though some of them can be sticklers for originality
as they tend to lean more toward the restoration side of the hobby, but all Pontiacs are welcome. There is a wealth of knowledge for GTOs and Trans Ams/Firebirds and the Pontiac motor on PY.
If you were to repaint the motor, I would stick with the same brand to avoid any conflict between formulas. Or at least test a piece if you don't intend to use if you use different brands. Several members seem to prefer the Plasti-Kote 227 for durability, according to a recent thread there.
I'm fairly certain you can order any of the major brands from your local auto supply or even Amazon.