i have a baja 204 with a 5.7 it struggles getting on plane. I built the motor 2 years ago it has a comp 270 roller cam vortec heads edelbrock rpm intake 1409 carb 600cfm. The boat always ran great until i changed the upper gears i went from 1.81 v6 ratio and 23p prop planed great would run 55mph at 52-5300 rpm. I wanted to put the proper ratio in my drive hoping for some more speed. Now with 1.51 ratio and a 21p mirage prop it struggles to plane and when it does the motor will only rev 4400rpm at 55mph any help would be greatly appreciated

You need drop down to at least a 19" prop with that much gear ratio change. Probably should have just left it the way it was.