i recently talked to a engine builder for a drag bike(motorcycle) and he was telling me everyone runs turbo cranks which are same as other cranks but the difference is that on the throws of the crank at the bottom they machine notches in them with the bench to keep the oil/fuel flowing and from setting just at the bottom, he said he did some guys crank, just his crank, and after that he was scared to punch it all the way, his quote was like this i believe "turbo cranks are where all the secret power lies" if this is true, i'm sure we'd all love to know!!!!!