I relize this is not a new question but here is goes, correct me if I am wrong but from what I have heard the C6 tranny requires 60hp to operate,If it is behind a 300 inline 6cyl that is making 120hp stock at the flywheel then that does not leave mych for the truck to run on does it? would installing a rollerized C6 make a diffrence and what diffrence would having the kit installed on the life of the tranny for street duty, nother words would it wear oput quicker with the roller bearings insted of the bushings

 

Most of your power loss is in the torque converter, which is basically a hydraulic pump. I don't think adding roller bearings anywhere would help you out much. I'd slip a C4 behind that 300.