[RCLXT]

Ive been doing some homework on the 915 transmition for my V-8 conversion. You should talk to renegade with regards to theyre converstion kits. Even thought the transmition is intended for use with a V-8, its still attached to a 914. They have all the appropriate hardware to fit the 915 transmition to a 914, all the information you could want, and their price is pretty good to. If youre still not satisfied talk to Rennsport. http://www.renegadehybrids.com/ http://www.rennsportsystems.com/~porsche/ (respectivly)
The 915 will have rpm's vs speed similar to that of the 901 with the 7:31 ring and pinion. You can however get both 8:31 and 6:31 depending, although i would not recommend the 6:31 unless you intend to run 250 ft*lbs torque.