I have a 1.5 on a Bravo 1 but it's on an 18 degree deadrise 24WAC (Sportcraft). It has a 350MAG Horizon with a WOT rating of 5200RPMs and I can hit 5150 with a 15 pitch Rev 4 for a top speed of about 41. Cruise at 3600 RPMs is about 27MPH for abou 2.7mpg. Dropping the gear ratio I think will move you to a lower pitch prop to hit your WOT rpms. I don't know that it would improve your overall performance.......maybe Fr Frank will chime in
What kind of prop is it??