Jeff,
On my Univ 18 I go thru a 1x2 step-up transmission. I run very nicely at
2400, turning a 13x13 prop thru the 1x2 transmission AND I get 6 knt on
a Qt of fuel an hour. This is Measured and confirmed. No spec sheet no
calculation., a graduated 1/2 Gal bottle hooked to the engine inlet.

I done this because I didn't believe a engine could perform on that
amount of fuel. It certainly can!!

Ole Thom