I have a pair of 525sc's. One is being rebuilt as we speak. What can I do to these motors to get more HP out of them. They have the stock supercharger and stock pulley on them. Want to stay as reliable as possible but don't want to go to another set of motors just yet. What do you guys think?

I would leave them alone. I did a few things to mine and I gained a little power, but I don't think it was worth the time or money. You will be at the limit of the blowers and outdrives. Reliability may be a problem. With two engines it would get expensive quick, (pulleys, intercoolers, plumbing, fuel system upgrades, props, etc)

Roller cams, different heads, bigger blower, depends on how much you wanna spend and how much power you wanna make.

Switch to roller cams. Increase HP and more reliable with today's oils. What are your ultimate HP goals? That will dictate how much further you would go.

The engine I am rebuilding will have roller cams and better components. I will freshen the other up this winter if it makes it. I would like to see 600hp at the prop shaft. I know there will be a HP difference already from the freshen up and the engine I did not have to touch.

Bigger blower or go with a bigger pulley?

I agree roller cam conversion, quite the increase in power and response. Running those blowers at anything other than on the stock pulley just makes tremendous amounts of heat. Even with chillers they are still very inefficient for anything other than short bursts in the summer heat, and the heat can cause dangerous detonation. A larger blower is going to be your only choice for the consistent power increase level you are looking for beyond what the cam will give you. My old under driven 177 blowers would make great power for about 2 mins before the heat caught up

This guy has everything you need, one needs a little work however

http://www.offshoreonly.com/classifi...o52318-en.html