I stop using the bypass hose,I use to drill the head gaskets at the back to promote more flow,,now cometic has the hole punched in them.

Sutphen 30, suppose it would make enough difference if the fittings in the intake were aluminum an fittings, keeping the metals the same?
Whats everyones take on above the thermostat or below the thermostat? I was thinking of plumbing into the front water crossover. Id like to not add any more holes to the boat if I dont have to. Also had a thought of teeing into the 1/4" line at the rear of my merc/gill manifolds & tails.
Another concern I have is water pressure. I thought I had read of a pressure dump valve that goes in the main feed line after the sea water pump. I need to incorporate a few new things to this project. Water pressure gauge, oil temp gauge & an oil thermostat system. On a test stand I couldnt get the oil above 60* so until Ive irond that out Ive bypassed the cooler for now. Im hoping to find a thermostatic unite with minimal plumbing.

I plumbed mine right into the exhaust, I also printed up some flow restricters because I'm using -10 hose,
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https://cimg6.ibsrv.net/gimg/www.off...e77741a6b5.jpg

https://cimg4.ibsrv.net/gimg/www.off...4a0b990e44.jpg

https://cimg6.ibsrv.net/gimg/www.off...ed7795c329.jpg

Sutphen 30, is that on a GenVI engine? Ive heard of doing that. I have MarkIV bow tie's.

Did you experiment with different size restricters to achieve desired water temps and pressure. Just curious. I always thought about ball valves but like the simplicity and looks clean with restricter method. Saw them on another thread you posted years ago.

I’m not sure where your water dumps but wonder if exhaust helps pull some additional water.

Snowed most the morning up here. Wtf

Rookie, very interesting.. I was considering a similar idea. I thought of using the 1/4" line at the rear of the exh manifold to the tail to tee into using -4 an plumbing. What intake are you using? I have a Dart. I wish it had the boss's like yours for tapping into. Also, your cooler looks a lot like mine. What did you do for thermostatic oil control. Im looking for a solution with minimal plumbing. I tried to add some photos of my set up. Guess im not able to yet. :(

getrdunn, global warming.. lol

Yes, I also have a restricter in my bypass hose that I did drill out till I achieved desired H2O pressure. I also have a couple holes in my thermostats. Remember I also run my engines on the colder side. My E-Tops dump water 3/4 way out the pipes. I'm sure the water pressure is more than exhaust scavenging efforts.

I heard there was snow, go figure.

Those were Professional Products, but I have also drilled out my Weiand Steaths, Dart single and my Cutler/Holley intakes.
I run Jegs $32 165° sandwich oil thermostat. I ran for years without thermostats. I was nervous for the first month running thermostats because I wasn't use to the oil pressure drop after a long and longer recovery. I'll get pics later.

https://cimg4.ibsrv.net/gimg/www.off...f4139f8b3d.jpg
As you can see there is no boss to drill threw. The web there is in the way but just off center. I could either grind away the web, drill off center at an angle or get 2 new different manifolds, (rather not)..
https://cimg6.ibsrv.net/gimg/www.off...23ad923c5b.jpg
The 1/4" hose is want I was considering teeing into for venting the rear crossover.
https://cimg3.ibsrv.net/gimg/www.off...8e622cb6af.jpg
Current cooler. Need an oil thermostat set up with minimal plumbing.