72 340 Exhaust Manifolds.

gts340 said
3751084
3478823

These look like the casting #'s to me, if I can read the pic.

3478823 My guess is this one is actually 3418623 which is a 72-73 340 pass side exh manifold.

The drivers side is not an A body 72 340 manifold.

More likely off a 73+ 340-360 other than a body based on the casting dates.