water gauge show wrong tempherature

Is it only the water temperature gauge needle that "jumps", or do the oil pressure and oil temperature gauge needles also jump?

 

Does the gauge(s) jump when head lights turned on and off?

 

Dodgy electrical grounds can cause fluctuating readings. You can get a good check re indicated temps with an infrared temp gun checking the temp at the thermostat box and comparing it with the gauge. It's most important that the gauge respond consistently as the temp goes up/down, it's not too important whether it shows the correct temp. If the gauge is responding consistently, you can mentally note the correct operating range based on the IR gun and as long as the needle stays with that range, you know you are OK.

It's worth noting that thermostat temp rating is the point at which the T-stat BEGINS to open.

 

If you do a search on the "104628" part number, you'll get many threads about it -- it's used on many F models (but it's rather inexpensive so just replacing it is easier than making it a science project ).

 

It's been too many decades since I fiddled around under the airbox of a carb 308 to really know/remember. My guess would be that it's not super-difficult (since we don't seem to get threads complaining about it ), but, hopefully, some carb 308 FChatters who have done this replacement recently can comment.

 

With the oil filter off it would be easy to remove, you may even get away with leaving the air cleaner in place.

 

Sweet - Sometimes you get lucky! (Don't get me started on evap coils - not for an F-car)

 

Put lots of rag around it as water may gush out when you remove the sensor or drain some before removing the sensor.