How do you run the boat? Do you normally run short sprints, or do you run hard for long length of time?

I ran the race boat oil cooler on a line leaving the heat exchanger (closed cooling deal), the reason I did that was I wanted to oil to be able to be heated quicker too, the cooler was somewhat over sized and we sometime saw water temps in the river in the low 50's..

It is my humble opinion that you should run it on the outlet of the engine, the oil has to get over 220*F to really burn off any moisture, but you don't want to exceed 250*F or so, typical water temperature leaving a Big Block Chevy on a jet is about 140*-150* tops, so cooling the oil is easy with that kind of water temps...

I am sure there are more opinions out there, so don't take mine as gospel, it's just the way I do things  

You could always run a three way valve and throttle between warm/cold, just more plumbing and more headaches...

With my 468 Chevy, I run the water from the t-stat housing to the oil cooler then to the dump line. Oil temps run in the 190*F to 240* all day long, never had any issues.  I am not using the Dan Olson cooler BTW, I use a custom tube in tube cooler I built special for this boat.

GT

Shit I'm running my oil cooler from the seastrainer, and no temp gauge. I better get on that b4 running again. Can only have my foot in it for 30-45 min b4 I run out of fuel, dang old bbc, sucks down more juice than my gf at a open bar. What do you consider a long period of time? And 250% is prime for iol temp ? on a racy bbc vroom vroom?