If you keep the engine sprocket big, the gearbox sprocket small and the rear sprocket larger, with a close box, you should not do much damage to the transmission with the 500cc motor. I use to find that with the 4 speed CR box, I would choose where I would lose a race. It you gear for the ends of the straights you lose too much around the twisty bits. For the best on a short circuit, I used to gear low and let it rev out at the ends of the straights. The motor had lots of top end and if it revved out on a big circuit with high gearing, it became very exciting. It would cop 10,500 RPM easily and not blow up. My friend rode it at Bathurst in the fifties and scared himself shitless at the end of Conrod Straight. Then got up to Skyline Corner, hit the Armco fence and broke his arm and his leg - didn't race again for 20 years. They are a really good thing, however you always need to be 110% with it at all times. I think you will love it.