It's a SHAME the 455 got wet! Otherwise, that engine w/nothing but a set of pipes and maybe an intake (not that it really needs it, any more than the Pontiac would, as long as they're 4-bbl intakes) would run great in the T/A- even (especially, I should say) w/those highway gears that are likely in it now.
I put a basically stock Olds 455 from a wagon, into a 1976 Cutlass (buckets, console, nice ride- but HEAVY) when the Buick 231 went south. That car was an animal.
But if the Olds was wet long enough to lock it up, like everybody says, it'll take a bore and pistons/rings to put it right.
But before you do anything, you might want to go ahead and pull it apart to see exactly what you have. You just never know... But be prepared for the worst.