Use the 4mm LR crank, buy a 68mm cub top end and some PD big bore domes. On 100 octane gas with CPI's you should easily see 85+horsepower. The cylinders should cost around $1100.00 with cleanup porting, the domes 75.00, and the pistons 140.00. So for less than 1400.00 you have a damn hard running motor.And if you buy unported cubs it would be less than 1200.00!