I have a 1955 ford in need of temp sensor.  Has been converted to 12 volts.  Have read that the 1957 through early 60's were 6 volt.  So was wondering it I was to use one of these would I have issuse? 

You can use the 1957 and later 6 volt sensor but you will need an instrument cluster voltage regulator. Ford used them from the 1957 model year into the 1980s on some models. They mount under the dash in the wire that powers all the instruments and cut the voltage from 12 down to 5 to 7 volts. 

https://www.google.com/search?q=ford+instrument+cluster+voltage+regulator&rlz=1C1GCEA_enUS849US849&sxsrf=ALeKk00MeS90Y5yfx1mJ2U64dG-rATNnvg:1617918928085&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiPie_X0e_vAhUIna0KHS9kBUsQ_AUoA3oECAEQBQ&biw=1920&bih=937

I have a 55 T-bird that I converted to 12v. I'm still using 6v sending units and gauges, and they seem to be working as well as ever. According to Gil Baumgartner (CTCI-Gil's Garage), it's not necessary to change sending units or gauges to 12v. However, you do want to avoid using 6v senders with 12v gauges, and vice versa. 

Use the stock 55 sender - no reason to go to a 57 sender.  To do that, you would have to change the bung in the head as the senders (55 & 57) were not the same thread size.  In my 54, I used the 57 constant voltage unit for the gauges to drop the gauges down to 6 volt.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Thanks all for your great information. Great group of helpers!