I have a 2007 Monterey 234fsx. Came with a 350 Mag. w/300 horsepower. It blew up so I ordered a 383stroker w/410 hp. My original engine would turn 5200 @ 55mph, the new 110 more hp from US Engine will turn 4900 rpm and only do 50 mph. I have a 19pitch prop. Can anyone tell me what the...