1968 383 hp manifolds

The right hand manifold that you list is a 1967 B and C body 440 HP

Also right hand 1968-69 B and C body 440 HP and 383 HP (RR and GTX)

Hope this helps.

Not likely that this will work on an A body-early or later without modification.

The 67 up A body Big Block cars had unique manifolds.