Ol' Fart's Firebird Fantasy

[oldskool]

Originally Posted by Tony Corley

Looks like a good candidate to convert to a stocker from the pictures. Sell what you can't use off of it and install your stuff. Why haven't you bought it yet, lol?

Nope, the '72 400 has a 310hp factor. The 455 is only 315. It would be better. But those 455 heads had press-in studs and no end exhaust manifold bolt holes. And I don't have a set anyhow.

A '75 GP with a 455, factored at 300hp looks pretty good. And they show the 5c heads are legal on it. These heads are almost identical to the 6x heads that I have. And they have screw-in studs and all 6 exhaust bolt holes.

But, I just noticed that NHRA does not list any accepted replacement piston for the '75-'76 455's. They must be oddballs of some kind--maybe a bevel around the edge, or no valve reliefs. Anyhow, a barely under car at a divisional will most likely not be torn down to check the pistons. And I assume that if somebody requested it, NHRA would probably allow the same pistons they have listed for '70-'74 455's, since there would be no big performance advantage.