The color of that blue is called Lombard Blue and was used on Skybirds only.
Pontiac never made a 'big block' or 'small block'. Oldsmobile and Buick were the same way. The engine sizes as far as how external design was cast was the same across the board. This is why you can take out a 326 or 350 and replace it with a 455 using the same mounts. Only Chevy had different 'sized' engines that you may have to shoehorn into some cars.