On Wed, 13 Jun 2007 15:24:55 -0400, Gene Kearns
wrote:

I'm curious to know what the 200hp would do RPM-wise and Fuel-wise
with the 200hp..... at 26 MPH.

You really need some knowledge of the torque curves to answer that
question. Assuming the 200 develops more torque at the same or lower
RPMs, it should be able to spin a prop with more pitch and get some
extra speed or run at lower RPMs. Running at lower RPMs should be
good for engine durability, but assuming it takes the same horsepower
to run the same boat speed, fuel burn would be about the same.