383 motor on 15 foot Gto hull

[Fxdiaz12]

Hey guys I recently purchased a 15 foot Gto airboat with a 383 500hp motor what speeds should I be seeing from this boat at cruise and full throttle boat has poly bottom.

 

[0320_sled]

I have the same boat I’m running a sbc 350 h.o crate engine 330hp original to the boat from 01, I have a 2:1 ch3 belt box and brand new 79in r series prop cruise on my boat is around 33-35 mph top speed is around 48-52mph depending on load I am tbi injected with electronic ignition control

 

[0320_sled]

I don’t have Poly I have messed up slick bottom that needs redone badly