You can't convert an amp meter to a volt meter but you can put a voltmeter in its place. I did this on my OT Thuderbird Turbo Coupe. I used the needle from the Thunderbird gauge and used a voltmeter from a later model Ford. You do have to make sure the deflection from lower voltage to higher voltage matches the deflection of the Mercury gauge. I originally tried a Fox Body Mustang voltmeter but it went in the opposite direction than what I needed. I tried to reverse it to no avail. After the change it looks factory. I used the T-Bird gauge face. I set 12 Volt at the 0 point of the amp gauge. When charging the gauge goes up. When less than 12 V it goes down. I did have to JB weld the needle to the later model gauge.
Thanks I know the actual amp meters cant be changed over, but several companies do conversions on other vehicles. They take the face plate from the original car and install a volt meter to the face plate to function like the original. It can be made to show 12 volts at the original center and so would indicate charge when running like you did yours. I was wondering of anyone had found such a company that did conversions on these cars. Very common conversion for 60's/70's ford and Chevy pickups. Several companies do them. I was hoping someone might have also found a later model volt meter that would work in my face place and mounting.
Check with Williamson's in Arkansas. They repair all sorts of gauges so they may be able to do the conversion you want. and make it look like its factory.
I sent my temp gauge to Williamson's last year. He repaired and converted to 12 volt. He sent it back with the proper sending unit and the old mechanize. Works like a charm.
The Jalopy Journal
