Lost oil pressure while going through a deep hole, WHY??

Here is what happened. The motor is an amc 360. I was out riding with some friends and i went through a mud/water pit that was way deeper than i expected. I was almost out of it and the engine died. The water/mud was in the floorboards, and all around the jeep but not above the hood and i dont think it was above the intake. I tried to restart a couple times to no avail and winched out. Once out and after it sat a few minutes it fired back up no problem, showing normal oil pressure. It ran a couple minutes and then the pressure went to nothing. I pulled a spark plug, cranked it and no water came out. I ended up taking the bypass spring and plunger out, almost lost the cap as it was under extreme pressure, it bounced off my oil pan and went several feet in front of the jeep. Cleaned and reinstalled, put a new oil filter on, put some oil in the distributor hole, and a little in the oil filler. Started it up and had pressure again. Started it the next day and had 50+ pounds cold as usual. Finally my question. What caused this to happen and what can i do to prevent it from happening again if i am in the same situation. thanks

See my response in the full size area. Please don't do multiple posts of the same questions.

Thanks.

Bob
tufcj

The reason for the multiple post was that the question is relevant for both sections of the forum. Some people only read a specific section that pertains to the vehicle they have. Since the motor i am using comes stock in the full size jeeps, and basically the same motor thats stock in CJ's (304). I thought i would get a better response if more people saw the question, so i posted the question in both forums. this way i could get a response from both the FSJ crowd and those running them in CJ's etc. I didnt see this to be a problem, Sorry...