Made a phone call to ProMotion. All I can say is wow! Those guys really know their stuff. One of the many questions that was answered for me was information about T-56 input shafts. I didn't know that there are multiple different designs for the 26 spline shafts! Just because the shaft has 26 splines does not always mean it will hold up to your power levels. ProMotion actually build shafts in house. Most of the company's out there offer upgraded shafts that are actually produced by Tremec and only hold up to about 600 hp. I can't run you through everything Wally explained to me, but if you have drivetrain questions I highly suggest you call them! I will be ordering a full shaft,clutch, flywheel, quadrant, adjuster from the with my tax return for sure!