Is that the 2160 Trophy Hard top? If so, it's dry weight is about 2700-2800 lbs. What year is it; I'm guessing around 1986.
When new, it probably came with a 19 pitch prop and mustered about 4500-4600 rpm @ around 35-38 mph assuming a 1.98/2.0 gear ratio.
How long have you owned the boat? Has it always performed so badly? 3200 rpm @ 10 mph is not even on plane yet.
Is that the original motor(not replaced)?