You're probably right. I think I was mixing and matching years and HP figures to come up with 215 HP out of 230 inches. I also found out that there is a 330 HP 350, making it slightly better than the 389 for power to cubes. (The 230 at 250 just misses the 389's mark. But the 330 at 350 beat them both.)
But these are all factory ratings. I am SURE that a Ram Air 4 428 will post better dyno numbers than even the 421 SD. (There is a Pontiac aluminum Ram Air 4 manifold for a 428. It differed from the 400 slightly, but I can't find any real useful information.)
Also, correct me if I am wrong, but isn't the Quad 4 an Olds engine? I was always thinking the "Iron Duke" is the Poncho 4-cylinder powerhouse.
Now ... on to the REAL question.
A 455, with the right porting on the right set of 6X heads, an 068 copy-cam, factory intake, headers and the right gears in the rear end (3.55 to 3.73) will move your asterisk like nothing you've ever felt.
If you want to bullet-proof the bottom end, get a set of H-beam forged steel rods, (oops ... aftermarket!) ProGram 4-bolt main billet caps (oops ... aftermarket!), ARP studs and rod bolts (oops ... aftermarket!), BOP ream main seal (oops ... aftermarket!) Hey ... I wonder why Pontiacs need all this aftermarket stuff for the bottom end, and yet there are only two choices for heads? Makes you wonder sometimes...
Now, if you don't mind paying a lot of money for racing gas ...
