Yes you have to buy a flywheel a 28oz 164 tooth the one in your car won't work and the one from the wrong is too heavy.I know you can get it from Early Mustang AOD Conversion Kit, 1965, 1966, 1967, 1968, 1969, 1970, 1971, 1972, 1973 i believe someone said summitracing or jegs had one too.