Don't make to many changes at once. You won't know what worked and what did not. Make one change at a time and evaluate.

Looking at your hull and what not, I think the speeds you are seeing are in the ballpark. On a lightweight hydro with very little water friction speeds with your engine design achieve around 75 MPH. So with your V style hull and sitting down in it I think 60MPH is probably a real far goal, but doable if you find out what works for your applications. most of the advice on here for that engine will be from a hydro standpoint, and not a V hull. Mod engines like to be tweaked to a specific application. So what works for the 400CCMH group in APBA might not work for you. You are loading the engine more than we are with the hull. You might be able to rig up a simple water break dyno and simplify your testing somewhat. It would at least save you some time to find the ballpark and then tweak with actual test time on the water.