I was wanting to put a water pressure guage on 500 hp carb motors. Where is the best and most convient place to tap into the system? There is a plug on the thermostat housing but with water going in all directions there is that a good place to get a accurate reading?

Any suggestions?

You need to run one from the block what either side is easiest to get to your dash. The drian plugs on the block is the best place since that is where you will get a most accurate reading.

see the plastic line and the brass fitting that goes into the block, that is a good place and easy to get at, I can not remember what size it is i believe it is 1/8" npt fitting.

If you do not have one with your gauge, then any home improvement store will have one.

good luck

Ah thats what I was afraid of. While I had my motors out I put a hose barb in those spots and connected a hose with a 1/4 turn valve on it for easy access to drain block. Have hoses running forward and valves in bottom of bilge where i can reach them.

Think I could tee into one of those hoses on each engine, hoses may be 12-18 inches long. That should still give me an accurate reading right?