looking for a fuel sending unit 3/8 with 3/8 return

67Dart273 said

How did you do that without cooking the wire entry?

I did mine rather "redneck" but I "effed up" I put in a 1/4" istead of larger. At the time this was for vapor return

Punch don't drill a hole in the drained tank. Use a taperd awl and swedge/ enlarge the hole. This creates lips on the hole to reinforce
Fill it full of nitrogen/ CO2 through the vent or fuel line
......And braze it in.........

Click to expand...

I had the unit out of the car, used a step drill to carefully enlarge the 1/4" return hole ( used small micro torch to heat and remove original 1/4" fitting) until my 3/8 steel tube fit tightly and used 2 small pairs of vice grip plyers to act as heat sinks while I silver soldered the tube in place. The wired bulkhead was added after the tube was soldered in place. I sourced that from Radium Engineering, but there are other sources too.