[asphaltgambler]

Pontiac had everyone beat, with the 421SD at that time. While rated @405HP at the flywheel, the actual number was significantly higher - @460+ believe it or not. That's from a stock machined production engine, before blue-printing and tweaking.

Also unknown to most that Smokey Yunick had considerable involvement/ contribution in developing that engine and platform. If I remember correctly, there was a specific frame and suspension set-up only to those cars. The frame was from the sister car convertible.

Smokey did as much for Pontiac up until the ban, as with Chevrolet.

If you go UT, there is a dyno test on absolute bone stock dual quad solid lifter Chevy 409 and the 421 SD. While Pontiac obviously has more cubic inches, there's a lot more the dyno tells us. Good stuff