I watch 4mills run with ten mills and bigger all the time. I have a 375 stock cylinder shee and i can keep up or beat bigger bikes. All in the setup gearing tires etc. Smaller motors are a lot cheaper to build and rebuild.
Cory with compulsive is the fuckin man. I wish he sold more then electrical id buy anything from that dude. I bought just a fuckin 50 dollar ignition and dude helped me out till the end when i ran into problems that weren't caused by his harness. This dude never not answered my calls even on a late night before a pismo trip. Great fuckin dude