installing mechanical water temp gauge in a 340 engine

[miketyler]

I need to temporarily connect a water temp guage to my 340 so I can confirm my factory guage indication. The problem is I can't see where to connect it. The only location in my MP intake is next to the t-stat housing and is too small for the probe and looks like a 5/16" fine thread?

Someone mentioned teeing into my heater line but I didnt see any such hardware at the auto parts store. Maybe we're talking conventional household plumbing hardware? I suippose the best pace for this is as close to the thermostat as possible so you are getting the exiting water temp? 

Please advise, I should have done this a long time ago.

MRT   

[Chryco Psycho]

in the past I have used electric aftermarket guages in small blocks , the sender for those is 1/8" NPT [Pipe Thread] same as the factory sender