Let's start again...
beerjet was trying to spur you for more information..
There are a few different causes for the banana milkshake.
First, how much water are we talking? Is the oil just a little milky, or did it actually raise the level?
Where was your water temperature running?
Has it done this before?
What motor? Seems irrelevant, but the Ford 460 and the Olds 455 both have substandard intake manifold designs around the water ports.
Basic causes...
Intake gasket leaks, this puts water right down the lifter valley, could be related to pressure, but doubt that on logs.
Cracked block, this could have numerous causes and can break in a whole bunch of different areas, normally due to freezing.
Cracked head or pulled valve seat.
Cracked exhaust log, easy to verify if a two hose manifold, simply block off one hose and pressurize the other... Should hold 20 PSI of air without issue.
Cracked riser, more difficult to diagnose.
Cam duration and lobe centers, if you have a lumpy cam, it could be reversion, this is especially true on a log deal.
Water left in the bilge while in storage, if the water level is deep enough in the hull to go above the front or rear main seals, she take take water in without you being the wiser.
Head gaskets, probably last on my list unless the heads were torqued improperly or it severely overheated.
Over pressurization, difficult to do with logs, yet not at all impossible...
Hope this helps and hope something sticks out...
GT
