Can anyone identify this exhaust casting #

redfastback said
It was used on 340 equipped 68-71 A bodies, and 70-71 E bodies.

Yep Std fare 68-71 340 A & E body exhaust manifold. It's worth 100-175 IMHO.

Correct on the pass side, gets the most money because they crack easily and were not in production for the 71 model year.