At 2900 hours SMOH your engine is still quite young. I would install new pushrods at the least. Probably new adjusting screws for the rockers, pull a couple out completely and see if the nice round ball on the end is becoming lopsided. Also for $185.00 each I would probably replace the rocker shafts unless you are positive they are not worn, mic. them. The rockers themselves are very expensive ($185.00 per each, times 12) They are very tough but they can wear, check them out, there should be very little, if any play between them and the shaft.
It's a PIA to get the injectors out because the bleed-off tube must come out, don't bother trying to get them out without taking off the tube. If my memory serves me though, I don't think the injectors need to come out but it is a very good idea to remove them and have them "pop tested" or just rebuild them. The head is so heavy and the injectors extend beyond the surface of the head that you will probably damage them just moving the head from boat to truck to shop.
There are little caps inside the end of the rocker shaft. You can knock them out and reuse them although they are cheap. The caps go on the front end of the front shaft and in the back end of the rear shaft.
While the head is off, make certain the bleeder valve on the port side of the exhaust manifold is free and working. You will need to open it to allow antifreeze to flow into the cooling tube which runs at an angle along the starboard side of the engine. Overheating will result due to an airlock if you don't get the tube filled.
Removing the head is actually quite straightforward. If it is in the way remove it.
American Diesel is your source for parts and information.
Good Luck, send pictures
pete
