Originally Posted by whirlcap
Hmm, getting quoted on this a bit and I fully admitt, I know little of the motor swap myself. Heard the P-51 motor is more powerful and slips right in more or less? Could be I read it wrong, might be a different UM motor. The more I think about it, the more I think my Champ will stay stock.
True. 51 motor is direct replacement but has more power.
Solo pro has same power, is cheaper, but you have to change the spur gear. Some say it lasts longer than the HH motors. Perhaps