Correct water plumbing for my v-drive

[johnny2slick]

I am running a 502 chevy with a 622 lift comp roller cam in my v-drive with a magnaflow water pump and bassett headers.
I recently bought a 4-outlet temperature control setup to replace the two-outlet thermostat housing and I have some questions regarding the plumbing to the headers.
A friend of mine has set up his jet boat with one of these units and has changed the plumbing so that instead on one line going to the header tee and one exiting the boat through the gate valve, he has set it up so that both lines from the temp control now exit the boat, and he has ran a fitting off the intake next to the temp control (where you would normally run a plug or a sender) and directed this line through a gate valve and then to the headers. This way he says he can control the flow of water to the headers independently of the main flow of water, thereby reducing block pressures by having two full time unrestricted outlets leaving the engine.
My question is this...I can see the need to do this on a jet boat due to the high water pressures entering the cooling system from the jet, but will this arrangement work in a v-drive?
I want to try and have a reasonably steady engine temperature and create the correct amount of coolant pressure in the block, and also have control over my water flow to the headers.
I have also been told that with some camshafts you will end up sucking water into the engine through the headers and causing a hydraulic situation or sucking it down into the crankcase.
Can anyone shed any light on this so that I can confidently plumb my water system.
Many thanks!

[ss396]

:idea: hey johnnyslick come down to moses lake on sept 16 and 17 and you can talk to circlejerk and many other v-drive boat racers and watch some great boat racing we are having AOF Nationals there also bring your v-drive for the show and shine. i am in the final stages of getting my sanger ready for that weekend and i am putting in a water shut off to the headers so that when i am ready to turn the engine off i can shut off the water to the headers so i do not suck water into the heads so i do not suck water into the heads. circle jerk has that setup on his lavey and it works great. see you there :)

[DUCKY]

The water in motor situation is a real life fact. I would run it like the instuctions show, with one bypass from the t-stat going directly overboard and one tee'd off to the headers by using a Bassett tee-valve, but put a restictor inside the inlet on the tee-valve. A 1/8" NPT socket head pipe plug (brass or stainless) epoxied into the inlet of the tee with a 1/8" hole drilled in the middle works well. Your goal should be NO WATER and I repeat NO WATER to the headers at idle, and nothing more than a mist and steam once you are on plane. If you have raw water dribbling from the headers, it's too much. I do not prefer the use of adjustable valves anywhere on the cooling system.