the NV4500 "DOUBLER" is what i swapped into my 83' K20, it came from the factory with a 700R4/NP208,then i went to a T350/NP205,then to a hydro clutch SM465/NP205 , and now the 5 speed doubler behind a Cummins , most of these trans swaps are fairly easy, just a matter of collecting all the parts