If you plan on running the 13.5, I hope you've got some BIIIIIIIG pinion gears. There's not much hope of running anything lower than 108T spur. A 100T with 41T pinion was about a mile off. :-O
I guess I'm just a gimp. The PRS thing is working fine now, I just made the slot longer with the dremel. I guess I could have filed the pin too. Now I've just got a snug fit so that the layshaft can't move side to side at all. I checked everything mentioned here and still no luck.
Mounting a GTB in this sucker has been interesting. I ended up having to do it like the picture of Todd's car. Otherwise, the belt is in the way and the ESC is hanging off the side too much.