I'm looking for something in between a full drag motor and trail motor. I plan on running it mainly at the dunes shooting hills. Might put a 4" extended swingarm on it. But I will be riding it in the mountains every now and then. So with that said I want as much top end i can get without it being a pain to ride on the trails. What should my squish angle be for the head? I will run straight 110 race fuel. I can bore my carb, how much should I go or is there a better rout? Thanks again. Thanks el diablo, I have a machine shop that does work for me with my snowmobile builds. They bore my carbs and machine my heads to the specs I give them. I will probably go with the 41mm carb bore. But what about my head? As far as the bore that's the first thing I plan on doing is finding out where it's at. Machine inserts for the main bearings? Is there a known problem with the bearing to case fit? And is it really necessary to do all that to the transmission? Sounds like overkill to me? Also top bearing and thrust washers? Is that to prevent piston movement? Sorry for all the questions I have experience with modding snowmobile motors. Just trying to figure out the weaknesses of the motor so I can decide for myself what is necessary. Thanks again for the info. I am a sponge, let me soak it up