Hi Guys,

just had the heads redone on my Merc 600SCI's (375 hrs), new springs, seats ground, All new valves, keepers, etc. I did not have any porting done as I am trying to keep the engine as close to stock as possible for reliability. Pistons and cylinder walls look like new. What, if any, performance gains do you think I may see after this is done.

thanks,Mark

did you do compression checks before and after?

did you replace the lifters?

I woudn't expect much improvement unless you lost something before.

If you did not change anything what would make you think there will be any improvement in power ?????

Only way you're going to see more power from a Merc 600sci is to increase the boost and change the camshaft and intercooler with special ECM programming.
Talk to Dustin at Whipple, he has some so far successful upgrades for this engine package. I don't think anybody can speak to the reliability so far as they have not been in use long enough yet to get accurate feedback on reliability and longevity.
If its done right I would suspect it should operate like the 700sci and thats been a very reliable supercharged engine package so far. The real problem may be the drive as power levels over 600HP have been known to make XR bravo drives give up the farm on some boats with some operators!

Best Regards,
Ray @ Raylar

The only thing you will gain with a standard top end refresh is any power that was lost due to valves not sealing or weak springs. Unless something was in bad shape, you probably won't see any real gains...........but the engines should go another 375hrs and be relatively trouble free.