Replacement manifolds for 360 in a 74 Duster?

The 72-76 340 / 360 a body manifolds are cheaper and more plentiful than the earlier ones, although they don’t perform as well. That is what I used as I didn’t want to spend the big money for the earlier ones.

Some use Jeep manifolds on the passenger side.

There are tons of threads on this subject, do a little searching.