To help you identify what year planetary gear set will fit your 727 transmission/out put shaft, please read and click on picture to the right. Output Shaft Tech :Going from top to bottom, 1st shaft fits 62-64 727 push button. 2nd shaft fits 1965 cable case 727s only. 3rd shaft fits 66-75, 4th staft fits 76-93. NOTE: all 62-75 shafts use the same front planet splines (45*) The 76-93 shafts uses a (37.5*) front planet spline and has a extra groove (see pointer in picture) near the slip yoke splines.1994 and up 727 shaft not shown in picture. Note: Our hardened output shaft only comes in 1962-1975 spline. If you have any questions please call and ask for John Cope.