Hey Folks: I've got a 55 fairlane with a 272 in it and I want to install a manual water temp gauge, and I thought I would see if anyone knew where I can get one? The gauge that is in it is working but its fluctuating some, when I check the car with a ir heat gauge it reads about 170 at the top of the radiator and about 150 at the bottom. The sending unit reads 180. Id like to know what temp it is running.

Do you mean an aftermarket one?  I would shop around on Summit and see what you like, if so.  

Sounds about normal, and good to me if you’re running a 180 thermostat. The delta between top and bottom of the radiator will vary with the ambient air temperature, but if you’re in a moderate temp zone, a 20 degree drop seems ok.

The engine temp will vary at various spots in the water jackets. Warmed up, thermostat open, the ir temp on the manifold at the thermostat (alongside really, on the intake) is what the temp is running there. I think most people consider that the “running” temperature. It may very well be slightly different at the sender location at the back of the head. Someone posted that difference once, but I don’t remembered what it was.

As to adding a gauge, I drilled and tapped my blue thunder up by the thermometer housing. Finding a mechanical gauge where the bulb will fit in the stock location might be a problem. I’ve never looked for one that small.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Also, if you're worried about thermostat I HIGHLY recommend Napa #6 - a 170* thermostat.  I chased all kinds of issues with thermostats of various temps and no thermostats...in the end, that thermostat made all the difference.  

I believe 170* was stock in 1956!

56 Vic, B'Ville 200 MPH Club Member, So Cal.