crusader 454 help.

after launching my boat this past week while to the morning we over heated and blew a head gasket i think while heading to the mooring .after getting to the mooring and draining the engine oil i got the dreaded milkshake oil coming up . spark plugs look ok when pulling them .
my plan of attack for the weekend was this:
1.refill with clean oil and perform a compression test.
2. if compression is good begin to remove parts all the way down to the head and inspect for cracks.
3. no block cracks i will replace all gaskets and heads with new
4. do a few fill and drains to get back to clean oil.

this is my first time dealing with a situation like this so any advice or help would be appreciated . i have the crusader repair manual and was curious if there is another manual that goes more indepth about the assembly of the actual engines .

thank you !

did you check the oil before the day started? curious to whether this is really a 'new' condition?? the sooner the contaminated oil is removed, the better for the bearings...

I'd start with a pressure test on the cooling system, ideally at a 'quiet time' at the mooring...if the pressure doesn't hold, you can get lucky and locate the leak source by listening. I'd also check the coolant level to help in isolating the source of the water intrusion.

Last item is don't forget the oil cooler can introduce raw water (vs coolant) into the crankcase as well...though this path usually lets oil escape via the exhaust as well...

as far as the manual goes, most of the OEMs use the GM provided service data for their manuals so there usually isn't much difference between them...that said, the factory manuals are always better than the aftermarkets...

so the engine overheated , and i had a buddy up on the bridge. seemed the raw water pump was loose, titghetend the belt up to get the exhaust flow back to normal . unfortunately when he started it he had the gas somewhat juiced up. i was getting condensate out of the breather hoses etc . after it started up again the temp began to dive and oil pressure dived with it . shut it down at the mooring moments later and got all the oil out . the oil was pure milkshake and the coolant expansion tank was low.

edit, ii pulled all the plugs and didnt find much condensation etc on them so i am hoping the damage has not gone too far .