Yes, wouldn't work for an all original resto but it's brand new and many members use them on the early A bodies because they fit and flow better than the stock 273/318 manifolds. The 340 manifolds like this one have a 1 7/8" exhaust hole while the stock 273-318 has a 1 5/8" exhaust hole. Why would someone buy a used one when they can get a brand new one??
