I've got a '67 mustang with a '74 ,302 engine. I've accepted that the needle on the Temp Gaugegoes 3/4 the way or better to HOTwhen the engine is up to operating temperature. I've tested the temperature of the coolant in the radiator tank when hot ; 190 degrees,so I believe it's cooling properly. I'd just like to be able to look at the temperature gauge with confidence that the car isn't overheating. I replaced the sending unit. I used one listed for the '67year with 289engine. The gauge is orginal equipment. Is there a way to calibrate the gauge,replace it or something?

 

You have the wrong sending unit. You need the one for the 74 302. It all depends on the fitting of the sending unit. It needs to be the correct depth to give the correct temp reading. In fact if I use the temp sending unit that the local parts store sells in my 70 Mach 1 351 W I get the same type of readings that you are getting. If I buy a sending unit that is OEM for the 70 Mach 1 351 W it works perfectly. Not to mention that the two different sending units have the same thread size, but have different body sizes. The gauge is stupid. It only reads what its told.

 

Thanks Bodyputtyless!
When I replaced it I just matched it to the one that was in there.

Could I press anyone to give me a site to buy a temp-sending unit for'74 Ford 302 engine? Not lazy , just looking for a short cut.

 

Walk out front door. Beware of bright glowy thing in the sky, it's just the sun, you may have heard of it. Get in the car and drive to a parts store. They have lotsa stuff there.

J/K. Couldn't resist.

I would suggest an aftermarket temp gauge if you're worried about it. An Autometer electric gauge would be my choice. You could mount it in several different places to either conceal or show off the gauge. You can put that sensor in the thermostat housing or somewhere else on the manifold to keep the stocker. You could then compare the 2 gauges and figure out where your stocker reads for sure.

 

I'm conficted .So is it match the sending unit to the gauge or match the sending unit to the engine.
OK. Heres the deal I've tried three sending units. And tonight I put in the fourth ,one that has about one third more resistance, 22 ohms compaired to 15ohms. When I run the engine tomorrowI hope I can get a satisfactory reading.

 

"I've tested the temperature of the coolant in the radiator tank when hot ; 190 degrees,so I believe it's cooling properly."

I have the same situation.
I would recommend you do nothing. You have a base line at operating temp. Go with it.

 

Bodypuddyless is right,match the sending unit to the motor.NOW the temp in the starts out at room temp in the radiator tank,gauge needle at C ,when the motor has run to operating temp the Radiator temp goes to 190 degrees and the gauge now hovers in the mid range. I'm satisfied.

 

just buy a mechanical guage and be done with it plus they are cheap