87 omc 75 (56ci)

[hydrostreamcrazie]

i have a lost foam case 56 ci powerhead on a 15" mid and was wondering what i can do to make it go? can you cut the tuner at all? i was told to cut the head 25cc for pump gas 21cc for race gas, that sound right? also timing, anyone know where the sweet spot it? im going to best 1000ft run. thanks

[terry taylor]

Nice engine, what,s it running on for a boat thanks ?

[hydrostreamcrazie]

Its on a hydrostream hustler v pad with a manual jack plate.

[terry taylor]

With that you should be turning good rpm,s ,raising comp. might allow more. Are you prepared to ramp up timing, jetting, and rpm, for a little gain and sacrifice reliability? If this is the nitro gear case with a worked prop. I can understand if this is for competition use thanks.

[hydrostreamcrazie]

Yes this is more for competition use so I'm not super worried about reliabilty. It is a smaller gearcase but I don't think a nitro one. What should I run for timing? And as far as the cc's on the head cutting, did that sound right? Thanks

[terry taylor]

My questions have been to help arrive at the answers thanks. Your full throttle rpm,s as of now, also your prop dia. and pitch will help others input their knowledge or experience. Myself I am not sure of a recommended answer[s] thanks.

[hydrostreamcrazie]

I'm running 6000-6100rpm. I'm spinning a 11 1/4"x 23 over the hub chooper. I have boysean reeds, no air box.

[powerabout]

port it to the sst 60 specs and use the megaphone to suit
apba class specs here www.opcrace.com
If its a 56'er its 70 hp at the propshaft there never was a 75hp 56ci