Fuel Gauge wiring (rewiring to fuel cell)

If you're going to tie in permanently there are a few very strong ways to do it. I would use a lineman splice if you have a soldering iron it's very strong.
P.S. Don't forget tyhe heat shrink, electrical tape melts off and is gross to clean up. https://makezine.com/2012/02/28/how-to-splice-wire-to-nasa-standards/