"Dave Covert" wrote in message
...
I notice that most auto engine conversions use a gear box between the
engine
and the prop. Why is that? Is it because an auto engine's peak HP is too
high for a prop to swing? Is it because auto engines weren't designed to
be
pulled around by their crankshafts and don't have proper thrust bearings?
Both?

Are there any auto/motorcycle conversions that don't require gear boxes?

Dave



Because the RPMs at which the motor is producing the proper amount of power
would be spinning the prop to fast.