Dj-Chuy
+1y
"sending unit" is just what tells your guages how much fuel is in the tank.
When I got mine, I had to put a Holley Blue Pump to run it. Normally the tank has the pump inside the tank. I went and tried every pump O'reilly's and Autozone sell and they were not giving me the pressure I needed.
I had to get the High Performance Fuel Pump to run it.
Haven't had a problem since.
(KNOCK ON WOOD).