Whether it's 2bbl or 4bbl will make a big difference as well as cam. I read that the only difference between the Firebird 330hp and GTO 350hp was a restriction placed on it. I don't know remember what that restriction was.

I don't know what stock intake that's from but I would think that setup would give you 330hp if it's a 4bbl.

The more common, higher hp heads were 16, 62, and 48 for 69. You can check the bottom of this web page for other heads: http://www.yearone.com/yodnn/tech/Vehicl...23/Default.aspx

The exhaust system will also effect hp. I don't think there was a difference on stock exhaust but I'm not sure on that. Adding headers or different muffler, pipe size, etc can make a difference. I think 2.5" pipe is optimal on the 400.

Relating to what Firebob said on hp, back then the 330hp was figured from the flywheel and not the back wheels.