Hi Bob,

As I'm sure you know, I'm an RCV SP fan for thier ability to fit in a tight cowl and turn a large prop. Perhaps the CD version will meet your needs. The CD version runs 1:1 and turns a conventional size prop but still uses the rotary valve. This means that it doesn't have the tall head that other 4 strokes need for conventional poppet valves. It's profile is more like a two stroke, and may fit your need.

Scott