26sonic

am looking to upgrade my twin 496 ho engines to 500-525 hp , anyone out there with this hp range? what props and speeds are you getting?

Plum_Crazy

There are some 31's on here with 470HP 500efi engines. I believe they run low 80's. Maybe they'll chime in. You should be looking at mid-80's. What mods do you have planned?

26sonic

either going with raylar kit or considering tyler crocket kit. heads , cam etc.

sonicss42

Bob Madera aka RMBuilder has a very good reputation for cam selection on all the go fast forums.

45SS

I had one with 500 EFI's. It's best ever on GPS was 83. That was with A/C , Ref. , electric head,. Jimmy D. has it now with BBlades reworked props. Jimmy told me he has seen 86, and I believe he also state that he had to take the A/C out.

Plum_Crazy

You know, I've never used my A/C. That may have to come out this winter.

sp123

if you guys can let me know how to get that kind of mph out of a 31, I would appreciate it.... I have new 8.2 and it runs approx 68mph at 4400 rmp... cracked 70 once but that was it...

kjberman

4400RPM??? Did you state that correctly?

My 03' 31 with HO's ran 76 with BBlade Props at 5k RPM - Even hit 77........once.

glenncal1

sp- what props, I think those motors should be closer to 5000 rpm for max.

sp123

bravo 26" Merc rates the engines for 4400-4800 so i am in the range...perhaps some modification of the engines themselves to try to get more hp.. mine have 380 each, so I am sure I can do something to get more....$$$$$$ any prop suggestions???