I'm very interested in this! Any ideas or suggestions anyone? I not only want to know which 727 Torqueflight parts are the best and why, but also which of these best 727 Torqueflight parts interchange with the later 518/46RH/46RE, etc.? I want to build-up my 518 overdrive and I have heard that most all of the parts will interchange, (with the exception of the valve body) but I have not physically set-them side by side and compared them. I want to swap a 518 behind my Big Block 451 Stroker engine. Which parts will swap? Such as Hemi Clutch Drums, etc.?