69 Dart exhaust manifolds on E-bay.

Hi my Mopar friends. Can you give me a heads up on these exhaust manifolds before i pull the trigger from my wallet They from"Norms Speed Shop". Item num...- 121089182185 -They are 273/318 manifolds part no.s 2780945 an 2465769. But they will fit a 340 (which is what I need) is that correct.? Just bolt straight on. Do they have the same FLOW as the original 340 ex man..? Sand blasted an painted and gasket surface milled. $295. Seems like a good price..? Not too worried if not matching numbers. Any advice...??