thanks for all the info. i really don't know too much about the internals of the 4 speeds. never took one apart myself. that's kind of ironic cause most of my cars are 4 speeds. i do have an empty 18 spline cast iron case that i've had since the 90's. a friend of mine is gonna help me swap the cases. he's had these pro shift trans before. i wanna try it in my '74 challenger. i'm setting it up more for the track than the street. this year i upgraded to QA1 double adj. all the way around, strange 1350 driveshaft and yokes. and i have the RXT dual disc clutch. i have a 2 step and i have to setup the clutch pedal switch for the launches. maybe this trans is what i need for the track. once again, thanks for the info! you guys are great!