The Pontiac 455 used a cast iron intake manifold as opposed to Chevy's 454, though, which were more refined and used aluminum. In its most powerful form, the Pontiac 455's factory compression ...

With the single-plane carbureted intake manifold ... First introduced in the '70s, the 7.5-liter Pontiac 455 V8 would be used in many of the company’s models, such as the Grand Prix and Firebird.