one of the problams with reversion is not water comming up the pipe it is if your exhaust risers lets the water out close to the riser rather then down closer to the exhaust tip. you will get reversion due to cam duration if your idel is not above 750 rpm if the water falls out to soon.

Remember also if you have a MPI/EFI engine and run without a stat. the ECU will think the engine is still in warmup mode and run rich. I ran mine without because of the procharger, but Up here it's colder and I would get alot of condinsation. Now I run the Arizon Speed & Marine 120° stat, and had the ECU reprogramed to have the lower temp warm up mode. No more condinsation

I did'nt want to confuse anyone by inserting this into this thread but thought that there was more than one way for condensation to form in oil.Figured that if someone else had this problem it would be useful to know about if it was true.

Having just spent a ton on new stainless steel exh manifolds and all the associated goodies to make sure we did'nt get a water INCURSION problem ,I had heard during the work that sometimes you can have a mild reversion problem that (in our horrendously salty water) before it totally screws the engine can occasionally manifest itself as condensation in the oil and on the valve covers.
It would'nt take long before the valves started sticking first and then kaboom so its unlikely here that we'd get to the point of seeing water in the oil.. the above point about salt/fresh water was very pertinant !

ps the old Merc cast iron junk was about a week away from total failure and then we would have had a burial at sea for a much loved 502mpi with only 154 hrs.More people should know about this stuff huh ?

You can pour water on the engine and squirt it up the exhaust and unless you have a leak or the water actually gets into the piston, it cannot get into the oil. Just get the oil temp right, make sure you have good gaskets(esp. head and intake) and a pcv and you shouldn't have water or moisture in the oil or valve covers.