340 exhaust manifold fitment?!?

549 and 553 last three on the manifolds and you are good. Those are 68-70 340 manifolds.

T/A and AAR manifolds are no different from a 70 Duster or Swinger 340 set. 340 manifolds are not the same through the years.

http://www.forabodiesonly.com/mopar/showthread.php?t=204139