Years ago I had a Wellcraft 23 Nova with a single 260 horsepower small block Chevrolet. Now that obviously was not my crabbing rig. My crabbing rig was a 16 ft aluminum center console with a 50 horse Merc. But I built a stroker motor for the Wellcraft it made around $410-420 horsepower. None of the instruments are really that accurate but I think I was getting around 60 MPH with it