i have a early 525sc that has been completely gone through recently...stock comp. ratio, srp pistons, eagle H beam rods, Crane hyd. roller cam,(up one size from stock) inconel valves, crane gold rockers, titanium retainers, MSD ign with soft rev, still running the stock Gil exhaust, 1050 dom. My question is that I'm gonna start shopping for parts to do some upgrading and am curious as to what would be the better set up, both HP for the money and reliability. thinking about adding a super chiller and smaller pulley to the 177 or selling the 177 set up and buying a B&M 250 and running the stock amount of boost for that blower. the other thing im wondering is that I see the newer 525sc came with CMI E-tops i believe... will i gain much by switching to those compared to the factory Gil exhaust? Thanks in advance for the input.

I've got 525sc in my boat . Built and dynod to 600hp. How much HP are you looking for. Cmi is what you should be runing. Unless you can afford stellings. They displace heat better and help the HP a little . Some more some less. If you want to talk pm me.

I did the switch from Gil's to CMI's on my 525SC and did not see any performance gains at all. The Gils were cracked, so they needed replaced.
Merc switched from the Gils to CMI's for the last year or two of teh 525SC, but the HP rating did not change.

For the best power gain, I think you would be better off to change to a 250 blower and run 6-7lbs of boost, and even better add a chiller to it.

Let me know if you sell your Gil's. I'm running the factory logs on a 525sc Clone. Its an 88 454 Mag with 177, Holley 850, roller rockers, exhaust and intake valves and a #168731 Crane Cam.

How does that motor run? What kind of hp do you figure?
I also have '88 mags and picked up a pair of hawk 525sc setups w/intercoolers (don't think I have the room for the intercoolers under the hatch) and am trying to get as much info on setups as possible. Going to be next winters project so I can paint the bilge too while the motors are out.

The motor is in an 88' 242 LS Formula. It has 448 original hours and was 525SC cloned at nearly new. The motor pulls 4lb's of boost at 6,000' with a 5lb pulley. I rebuilt the blower 2 years ago and had teflon tips added. The motor seems to run strong considering the 242LS is a heavy 24' deadrise boat and I always run at 5,100' elevation and higher.