Thanks for all of the suggestions everyone. Bud-- The 431 just doesnt have it. I have run it on my turbo 35 and it is very tight compared to two other brp stock motors. I was careful installing it in the car, washers,etc and i did not do anything to the pinion gear before or after installing. Haven't taken it apart yet. Could be the mags have picked up something from my work table. I will check inside the motor tonite. The older motors just have way!! more RPM the the new "tuned" motor. As far as my gearing goes, I am running the new 52 t spur and diff seems to be very smooth. Oh yeah, the new motor pulls more than 9.5 amps at 3 volts on the t-35. Something must be stuck inside, let you know tommorrow. And glad to hear that the brp pinions will fit w/300. Thanks K1m.