Ugh.... Fingers crossed. Will find out this evening.
On another note, during my marathon of chasing down the problem, I checked the timing and it was way off.... Only 8 degrees advance at idle and around 20 @ 4000 rpm. Question now is would the blown head gasket cause the timing to be off or did the advance module go out and cause the blown head gasket? Hate to get it put back together only to have the same thing happen again.

that's because the timing curve on the 525sc's takes forever to get to total. So, human error like most things.

I've seen two 525SC's with blown headgaskets people have adjusted timing to total specs around 3500rpm. Tisk tisk ! I was just done at a boat only repair place.

Do some digging,I and others have posted what the timing curves are on these engines.

Here:
total is 35* at 4500rpm
Initalis 13* at idle.
Tbolt IV module is 22A

Torched the head between 3&5&7. Amazingly the block looks fine.
Gonna change the timing module just to be safe before I put it back together.

Not exactly good news but it could have been worse.

At least you got your problem tracked down... I need to find out how I got water into the number 5,7 and 6 cylinders on my 525sc motor... All the gaskets appeared ok. Next step will be checking head and block for cracks...

And your exhaust, why are those valves stuck open ? or were the springs pulled

exhaust leaking appears to me...have engine down for same issue, looks way better than that but killed a piston

Do you still have the Gil exhaust?? If so, that would be my guess. I had to replace my Gils on my 525SC at 250 hrs. Hairline cracks in the dividers just below the risers.