Something on the exhaust system / header, close to the head, getting hot with only a little or restricted flow of coolant/water flow across the hot part, and when shut down, the water gets into the localized heat issue area, and cools the area down?

Crane cam, crane lifters..I did not change anything except the heads.. and I adjusted them running the last final adjustment. The only thing i did not do is put the rockers, pivots, locking nuts and pushrods back in the same original places..As for heat, cooling..it does it when the engine is cold also..engine water temp on garden hose is 125.

The new heads 781's were machined to fit my old SS valves. I don't remember the sizes but it was bigger than stock..The springs were checked, dual spring with damper
new oil seals and they said they set the closed height of the valve springs to specs ?..Cam is 560 lift..236 dur @ .50 and 114 LBA.
Thinking back..When i turned the engine manually to adjust the rockers i did notice a click sound...not positive though

I'm going to pull the plugs and remove the rockers today
turn it over by hand and see if it makes any kind of noises

pics of valves..

When you dig into it today, check the pushrods to be sure none are rubbing the head.
You should be at about 3/4" preload on the rockers. That should translate to .040-.060 of preload.
Eddie

Check pushrod clearance through the cylinder head, check the contact point of the rocker arm on the valve tip, have you verified the pushrod length is correct.

+1

This is what I am leaning towards, but still a guess. Notice how it goes from a fast tick and slows down. Similar to when you pull the car into the garage and shut it down and the exhaust may tick for a few seconds. That's what it sounds like to me. Does it do it when the boat is in the water with possibly better flow into the engines?

I haven't measured them ..I do know that the ss valves are
.100 over stock

Did you keep all the rockers and adj.piviot balls together? Also did you use assy. lube on them?

No. thats the only thing i did not do...They are all mixed/matched..They did not go back to their original places..several people told me it does not matter where they go back on

I am interested in the comp cams steel rocker with the roller tip..also new pushrods.. I do not want to change the height of the rockers due to the ease of removing the valve covers without removing the exhaust.

I would remove the rockers and make sure there is no gaulding on the pivot balls and lube them and see if the problem is still there.