I had a 91 Gulfstream, with a 2000 250 ox66. All around performance was fine, but it was a bit thirsty.
Cruise, with a light load, was around 27 mph @ 4500 rpm, 15/16 gph.
The Gulfstream is a heavy boat and with a single outboard you need to be over 4000 rpm just to stay on plane.
I...