If you're talking about a 2x4 intake, the Offy is the better choice. The spacing of the carbs is generally noted for having better flow.
I don't remember which models. It would be for a singe 4V. If I had access to craigslist here at work, I'd post the pics. They are both on Craigslist for the Saint Louis area. I just searched "Pontiac intake" in the auto parts section. edit: Oh, yeah, It'd be mainly street.
I bought an Offy for my '70 Olds 350 because it was cheap on eBay. Have no idea which one is better...