Water Pressure Gauges for My Pair of Chrysler Outboards

[Gordon02]

Guys, I'm restoring 2 Chrysler outboards. The first I'll finish is my 1968 75 horse and the second will be the 1972 70 hp that I just picked-up for $100. I want to add water pressure fittings to both and neither has what I recognize as a hose barb fitting for this purpose. These are my first Chryslers. Neither has an overboard "pee-hole" as my several Johnson and Mercury outboards do (1978 and up Johnson/Evinrude models have the overboard indicator).

There is a small, stainless plug with a slotted head in both of the thermostat housings. The 1968 model has a separate, top-mounted thermostat housing and a solid,1-piece cylinder head. The 1972 model's thermostat is captured inside the water jacket cover in a thinner and lighter, 2-piece cylinder head. Both have the stainless plug. Would this be the place for a barbed nipple for pressure?

The 1972 model has a 1/2" square pipe plug on the left side of the exhaust adapter plate. The 1968's exhaust adapter plate is solid and not drilled or tapped. Would this be the place for an overboard barbed fitting and a tap to a pressure gauge?

Inputs appreciated! Gordon

 

[jerryjerry05]

Shiny screw on the top is where it would go.
The pipe plug is just that a plug for the water passage.
It's probably full of crud after all these years.

Take a bunch of pics and post in the rebuild or projects section.

 

[Gordon02]

Thanks Jerry. I have the factory service manual for these, but there was no mention of these plugs or their purpose. I had also checked YouTube for further information regarding the application and/or testing of pressure to no avail. The Google searches did lead me here though, so I'm glad that I posted up the question. Again, Thanks! Gordon

 

[jerryjerry05]

Most use that plug for adding a pee tube.

 

[Gordon02]

Mine will be doing both. I like the gauge because it gives a general health check of the cooling system by comparing pressures on each run. I'll add a T and a small line to the $6 plastic fitting that I'll drill and locate in the right/rear corner of the cowl pan. Thanks for the information. Gordon

Oh yea, Photos coming....

 

[jerryjerry05]

If you put them both on the same screw??
Not sure the gauge will get the proper readings??