Junk yard manifolds...?

You need original factory manifold for a Dart that flys over the power steering on the driver's side. Best of luck. Pass side is much easier, almost any small block manifold will work there.
I was lucky enough to find a driver's side manifold in a junkyard 35 years ago for a 340, to replace my 318 exh manifold. $20!
Someone had already removed it for me, and it was sitting inside the car!
Pass side I bought a new Chrysler part.