Water temp Guage Question

[50 F1]

I have a Sun Water Temp Gauge that I bought new in the early 80's. I have used it on the first go around on my 50 F1. The truck has been torn apart since 85. I lost the original temp sending unit that went with the gauge. With a lot of googling and YouTubing I am finding out that a original sending unit or replacement is a unicorn or if you find one it is $150/$250

I really don't want to get a different gauge because I have a dash insert built for the truck and it has a Sun Speedometer and water, oil and fuel gauges all matching.

I guess I have to find a temp sending unit that matches my gauges resistance from cold to hot, by hooking a sender up to my gauge with the sender in water heating up on the stove with a thermometer.

Where do I start? I mean how many sending units will I have to buy to get close?

Has anyone here went through this that can give me some pointer?

Thanks Mike

[kb426]

Have you seen this: https://www.technoversions.com/documents/SunTempSender.pdf

[50 F1]

Thanks KB
    Yes I did see them. My gauges are the smaller ones not the blue line ones. I am going to give them a call today and see if that sender would work with my gauge.

Thanks for the help

Mike

[50 F1]

KB

They only deal with emails, so I sent one out with my gauge info. I will see what they say.

Thanks again
Mike