Water Pressure Regulator (ARS Kit)
Designed to prevent blown head gaskets or leaking solid copper head gaskets. Allows you to add up to 20? degrees to your operating temperature. Maintains full water flow to engine, bypassing to a thru-transom fitting (hose not included) if pressure becomes excessive due to high RPM.
#ARS Kit 126 $125.00


or am i beter off going to  home  depot

I've heard you need it, and you dont need it.  So... I dont have one and I can run the water valve at full open with no water leaking into the oil...  I dont due to too much cooling, but I was thinking to get one anyways, I guess I'd call it insurance.  May not ever need it but then again you never know   I heard on Olds though it is a better idea as they are more prone to leaking.