I am looking at a 34' 1982 motorhome that has a Chevy drive train - a 454 up front to keep things going. It is in very good shape, but the transmission is slipping. It has a 3 speed auto in it. Is there a robust 4 speed automatic that can be mated up to the 454? It is a non-electronic engine. I am not sure if the 700r4 would live long, My goal is to get more mpg, and since it seems like the tranny has to be swapped, now would be a good time to get the OD.