I have a couple of 454's set-up similar to the 600sc's. I'm running twin 700 Holleys. I'm guessing that the compression is 7.5 or 8. I'm running right at 5 lbs boost. I have the 212* oil thermostes and crossovers with no water thermostats. My water temp is less than 100* and my oil temp runs about 180- 200*. I have aluminum heads. Stock oil coolers.

My problem is that both engines are set up the same but, I'm getting a lot of condensation in the valve covers on just one engine and its the same engine that has the oil thermostat. (You would think it would be the good one). I have tried a number of different brand oil thermostats but, that' as high as I can get the temps. I have tried replacing the intake gasket thinking it could be leaking but, that's not it.

Does anyone have any ideas as to what to look at next?

Thanks Bob

Intake manfold gasket? Have you tried tightening it? Maybe it's seeping...

You can buy a T-Stat plate...goes inside where your T-Stat would normally be , but is a disc that has different size holes in it so the water is not just pouring in...might help the problem..

Too much water pressure.
Do you have a water pressure gauge?
A buddy of mine had the same problem and added dumps to blead off some of the pressure.
I think he's running around 20lbs at WOT these days.
I think his oil temp is still a little low, 180-200°F

I have added a 5/8 restrictor plate. It may have brought the water temp up 2* not really anthing noticeable. My water pressure is still around 20 lbs.

Did your buddy bleed off water before it went to the engine and after the raw water pump?

I have double checked the intake bolts.

The only real difference between the 2 engines is that the one I'm having a problem with runs a Jabsco raw water pump in lieu of the Mercruser. I have noticed more water pressure on this side but, I would think that 20 lbs. is still good.

you need 212+* to burn off the moisture ...both motors run cold water temps ? The 20lbs ... at high rpms ?

I believe the dumps are off the exhaust manifolds so all the water still goes through the engine.
The dump hoses are pretty big, I think 1", same as the jumper hose to the riser. He stuck a pipe plug inside the dump hoses and drilled different size holes until he got the pressure right.
I think his water pressure is like 5lbs at idle and 15-20psi when up and running.
The engine is a built up Merc 525sc making around 575HP. Gregg still kicks himself for removing the stock thermo housing and circ pump.
An oil thermo is next on his list.

Your water temp is less than 100 degrees Fahrenheit? That's way too cold. Remember, you'll get some oil cooling just through the water a jacked of the engine. I would work on getting those water temperatures up first, then go from there.

Michael

Does one engine steam more than the other?