Originally Posted by violation98

Awesome info - thanks Eddie for lending the experience

Are the same Valve/spring/header etc issues and concerns also with the 600sci motors? I am looking at both 525 and 600sci boats and assumed I'd have less headaches with the 525s. Maybe not?

Originally Posted by violation98

I am looking at both 525 and 600sci boats and assumed I'd have less headaches with the 525s. Maybe not?

Originally Posted by Pwraddr

Less drive issues....the 600 still uses the XR.

Originally Posted by Young Performance

Yeah, I remember. You guys really bailed me out by replacing that shift cable.
In your case, there are a few things that I would do. That will differ depending on the year of your engines. If they are pre 2005 engines, you will need to do a few more things. You should pull the heads and freshen them up. Change the springs, retainers, locks and seals. Go with 10* retainers and locks. This will open up your valve spring choices drastically. You will probably have to surface the heads. You should be able to get away with just scratching them and only removing about .003 or so. When the heads are apart, go ahead and lap all of the valves in. If they all lap in good, there is no reason to do a valve job. Once they are lapped in good, number them so they will go back in the same location when you assemble the heads for good. If they are pre 2005, you should change the head bolts from the stock GM bolts to ARP's. Also go with Cometic head gaskets instead of the stock composite gaskets. While the heads are off, have a very good look at the rocker arms. Check for any loose bearings in the trunnions.

Also, I would certainly check the headers and tailpipes for leaks, especially if its a pre 2005 engine. Those were the headers that were really known for leaking. We have seen several sets of tails leak as well.

Once all of that is done, you should be good to go. The other thing you may consider if you want a little more power is doing Whipple's ecm tune. It really wakes them up in the mid-range. You will have to run 91 octane though. We have also done some with a little less timing that can run on 89 octane. It still wakes them up in the mid-range, just not as much.

Let me know if you have any more questions. I would be glad to answer them the best I can.
Eddie

Originally Posted by Bino

Eddie I have 525's in a 04 Top Gun with 330hrs. What would it cost to do exactly what you said here. if I wanted around 625hp, no more than that I have XR's is that possible or is it a whole different ball game. If so, how much more over just a rebuild?
Thanks Robert

Originally Posted by Bino

Great thread, as good as any I've read. Thanks for all the great info. I have a external leak now on my headers, do I send them to CMI?

Originally Posted by joew.

I have Eddie building one for me now. The cost to rebuild back to stock vs. stroking it are about 3k apart. Probably looking at around 17.