I run my Speedpassion 13.5 at 32/78 and will gear higher now that I have the new 75 and 72 spurs.
My buddy runs a Novak 13.5 and has it geared at least 33/75 and just keeps going up.... motor comes off the track barely warm on both our cars when running indoors.
We are running these in mod class.... and are completely convinced now that the 13.5 is too fast to be a stock motor when geared properly. My car will lift the front if there is enough track grip.