Around 25hp. The problem is the 177's lose efficiency and create more heat the faster you spin them.

So using the boat "normally", I.E. just cruising with short blasts here and there, shouldnt cause too much excessive heat. Right? Also may see a mph OR 2???

1-2mph is realistic. Cruising is not really affected because you're barely into boost, if at all. If you run a smaller pulley, change the blower lube frequently.

Griff, bought the 2.85 pullies, but dont have belts. Would you happen to know the NAPA part# for the belts you used to buy? I know its a long shot, but arent they expensive from a blower company? Not to mention, hard to find?

Gates Micro-V K100540

Sorry Guys. I started this thread, and my info was all wrong. For some reason, I thought it had the smaller pulleys. I have the 3.25 top, and 7" bottom. Measured them today. So seems i am not far off!

My engines are basically 525SC's, with dart alum heads, pretty agressive roller cams. With my current props, I only turned about 5000-5100RPM. I plan to spin them to around 5300-5400, as they really make quite a bit more power as the RPM's increase (cams). Good thing is that even with my current pulley, at 5400, Im spinning the blower at 11,718 RPM. If I went to a 3.05 pulley, i'd be at 12420 rpm. Im debating what would be better, spinning the engines say at 5600RPM, or at 5300 but spinning the blower faster..

Make sure that belt is on the "tight" side or it will probably slip. Once installed assuming a 2.85 pulley, I have had the best luck with the tensioner using the tightest half of the setting, looking at the allen head stop bolt in the slot on the drive snout-If that makes any sense..

Mild thunder-What are your current props?

any chillers for 177 blowers around? Is it 100 HP gain?

You would not gain 100 h.p. with that tiny of a blower. I would tend to think to gain that much just because of a cooler, you would need an engine about 540-598 C.I. and a 14-71 blower IMHO. I would think a real world increase would be 25 maybe 50 H.P. at best with any of these coolers.

They do make a chiller for them. I can't remember who however. I don't think it was Weiand