I assume the 79 fuel sender is unique but thought I’d ask and make sure.
Mine was sent and rebuilt about a year ago, not working again.
Ground ok, hooking up meter to wires, it’s open or intermittent all over the place.

 

I tested a 1979 fuel level sensor for someone's RX-7 today. It was pretty rusty but I got it cleaned up and working freely again. Also measured the empty/full ohms to spec.

Had the gas tank cleaned and resealed at a radiator shop and now in the process of putting it all back together. They did a fantastic job and also added a drain plug. I removed everything first before taking it to them.

If I had to replace it the fuel level sensor, I'd get a generic electric one like this and make it work. The biggest challenge is finding one that is close to the correct ohms.

https://www.summitracing.com/parts/s...RoCgecQAvD_BwE

 

I tried contact cleaner, brake cleaner, etc. It reads open most of the time, when you move it ohms go all over.
Im checking with Riggs Rotary to see if they have any, if not may have to send this one to another rebuilder and hope.
Nice idea on the Summitt one, but I’ve no clue on how to make it work,