This "big block/small block Pontiac" train of thought probably came from "Chivy" fans who are unaware that there is no visual difference in a Pontiac engine. Where the difference lies is in the size of the crankshaft. 326, 389, 350, & 400 cid Pontiacs used a 3" main journal, stroke was the same all of them, too. 421, 428, & 455 engines have a 3.25" mains. All Pontiacs used the same rod journal size. Block deminsions are externally the same. If you look at a Chevy you know if it's small block or big block. Makes me laugh to read magazine articles on Pontiac cars and the author refer to the engine as a "big block Pontiac"!
