Hello folks,

All my old heads from 64 to 72 use a screw in sensor for temp gage sensing of water temp in the head. They are about 3/8 in diameter (threaded) parts. My newly built 77 head with small tapered plugs and no plug tubes has a larger sensor hole.. about 5/8 inch threads, for sending unit. I can easily adapt the small sensor to the larger hole by using a standard pipe threaded adapter, but doing creates a potential problem.

The adapter is just long enough so the sensor doesn't go into the water in the head, it is stopped just about the top of the head. This means water doesn't circulate around the sensor, but in s in contact with the adapter and the bottom of the sensor.

What do you think...is this a problem that will force me to get a "new" sensor, and if so , does anyone have the part number or source? My usually great store gave up trying to find one.

Thanks
rock
'64d100

The '77 head has several different threaded ports. That larger-diameter one you're looking at wasn't for the temp gauge sender (which is the same in '77 as in '64). It's for the temperature sensor used in the emission control system in '77. Take a careful, close look at the top-front area of your '77 head and you'll probably find the hole needed to thread in your temp gauge sender. It may be plugged if the original '77 application used a warning light instead of a gauge.

The temperature gauge sender used in '64 and '77 looks like this:

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

SlantSixDan,

Many thanks. Your pic is my sender for sure, and nice to know there is both a sender hole and a sensor hole. I will plug the unneeded sensor hole and reuse the sender I have. I would not have flashed on this without your input.

Merry holidays to all!
rock
'64d100

Just as a humerous side note, the temp sending unit from a Ford 351 will fit the Bigger hole.......and works perfectly on a 63 Dart with heat gauge.

_________________
63 Valiant 200 Signet Convertible 170/
63 Dart, 225/
68 A100 Pick-up 225/
2006 Mitsu Raider Quad Cab (Dakota) Mopar 4.7L
1992 Dodge Stealth RT (My Mid-Lifer) 3.0L 24V

That's entirely possible. Remember, though, that the resistance range of '60-'63 gauges/senders is not the same as '64-up units.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.