If those ARE the 383 A-body exhaust manifolds, they may not fit properly on your 440 (the driver's side one has a big "kink" to go around the steering column). Since the deck on the 440 is higher and wider than the 383 there could be interference there.
I know there is a 440 A-body manifold too, but it's extremely rare and $$ if you can even find one.
