I used 360/340 exhaust manifolds in my '65 360 converted from a slant 6 motor. The pass side manifold was shaped like the 65 273 and fit nicely; the driver side had the same basic shape as the 65 273 manifold but the outlet was faced more forward. Both had larger ports and outlets. I had duel exhaust instaled $$ and liked the results.
I used an A body 8 3/4 and a 65 904 auto with a shift kit in the valve body and had no problems.