The Jim Carter catalogue says to inquire if you have an electric gauge. I'm not sure if this means they might have a sending unit for you or might have a gauge. You should inquire. I believe the electric gauges were used primarily on the bigger trucks, 1-1/2 ton and up. Post a 'wanted' request in the swap meet section.
You could also replace the gauge cluster housing with one that used a capillary sending unit. They are readily available as a used part and there are reproduction gauges available. If you get lucky you might also find a NOS sender.
Restoring the gauge cluster was one of the more satisfying jobs I've done on my '48 GMC 1-Ton.
