....
So anyway....
Buy either one, 425 or 455.
Neither of the 2 are 450 HP. (your goal)
So it doesn't really matter.
I'd opt for the 425 crank, but only if there's a matching flexplate, and it isn't junk.
I could draw up some blueprints of garbage can sizes if that will help the seller remember where all the engine info is.
