Is it splash lubed or oil pumped? Bigger pumps usually have an oil pump.
I
run my Quincys way slower than max, they will last forever. I think you
will not only NOT have a problem, you will LIKE the way it runs quiet and
cool.

Now HOW do you know they'd last any longer? A Quincy will last forever
anyway.

But, I think the OP has a good idea. gear it down to the smaller motor.

Karl