Here is my pressure release valve setup with a Merc pump and thu-hull pick up and strainer. In the charge cooler, that T with a gauge. Basically just a spring valve that dumps out the side of the boat. The water pressure gauge is about useless there, worked fine when setting it up, but once the hatch cover is installed, ya can't check it. An in dash gauge works the best.

http://www.altfuelsgroup.org/picture...922_160927.jpg
Pressure Relief Valve

http://www.altfuelsgroup.org/picture...922_160918.jpg
Sea Strainer

I also run that big block serpentine pump on this diesel. Mounted by a custom bracket someone fab'd out of aluminum. Works great, never an issue, but a real pain in the ass to change impeller each year...

so is the pressure valve the brass portion in the pic?

Yeah, the brass valve with the small hose coming off it.

water pressure
 

Cool, thx everyone, learned a lot.
I will run a regulator preferably off of the back of intake for 20 lbs, and then one in line be for the intercooler at 10 lbs.
Larry

If you are still looking for the sea water fuel pump setup I have a couple different ones with new bearings and seals.

still looking for a blue pulley 500efi seawater pump with pulley and bracket
 

About to buy new. Bracket 818368T1 with pump (no fuel outlet) pn 807151A22 and the associated pulley. My option is ti buy the bracket on eBay for 180.00 and a pump and pulley from harden marine for 370 for the pump and 175 for the pulley yippe