Originally Posted by Conquest 230

O i did not add a drive shower still running same one as last motor and same drive, the previous motor never blew the prop off never cavitated, but this thing is bad ,ver

Originally Posted by compedgemarine

first. why would it have a 1.36 drive? I cant imagine any one setting it up with a 454 mag and a 1.36 drive as it would be a dog. second, 69 mph at 5700 is around 25% slip with a 1.36 and around 16% with a 1.5 ratio which seems more likely.
the part I dont understand is if the boat ran good with the original setup and all that changed was the increase in horsepower then it should run the same now but pull more rpm. the boat handling as far as getting on plane and any speed up to the original mid 50's should not change. the only reason it would blow out now getting on plane is if the motor makes no bottom end power and has to cavitate the prop to get the power up. that should not be an issue with 500 odd horsepower.