If you're shooting for a #250lb engine, I assume you're already
committed to buying/making aluminum side housings..  You'll have a
tough time getting a complete engine/redrive that light without them.
The LSA Patrol is designed around C-65 to O-200's, right?

The LSA Patrol is basically the Patrol with all essentials thrown away. Claim
is that one go even go bigger than an O-200

Patrol is a 2000# gross airplane with 55 gal fuel tanks.
Bob Barrow's protype comes in around 950# dry with a moderate Lycoming (I
think he tried a an 0-320 but  now has an 0-360 in N289R), so I just picked
the 250# engine figure out of thin air.

If I could keep the dry-wt of airplane at around 850#, giving a useful load of
470#, I could even give my wife a ride.

Robin