The Performer is a decent intake, and will work well on a stock or mildly modified 326-400. On a 455, depending on cam and other mods, it's a bit restrictive. It works very well up to around 5200 rpm. The Edelbrock Performer is not a copy of a Pontiac intake, it's actually quite different.
An intake that was made LONG ago was called the P4B intake, which stood for Pontiac 4 Barrel. That intake was a true copy of the factory steel 67-72 steel intake, but was made of aluminum. They also made an O4B (Oldsmobile) and a B4B (Buick) that were copies of factory steel intakes, cast in aluminum.
The factory Pontiac steel intake is a pretty good piece up to around 5000 rpm, which is where most of our Pontiacs live on the street. The plenum can be re-worked, but unless you're willing to do a lot of work with a grinder, I would just leave it stock, and just port match it to the heads.
The factory RAIV / 455 H.O. aluminum intakes are reproduced, but are a little pricey. They are nearly identical to the steel intake as far as runners and plenum area are concerned, but they have a separated crossover, and are made of aluminum.
The Performer RPM is the best dual plane intake available for our Pontiacs, but it's a tall intake.
