3/8 sending unit

If you're going to plug it get a short (3") length of fuel line, plug one end with something steel and use a small hose clamp at both ends. With todays ethanol fuel there are rubber/plastic caps out there that'll get eaten out over time. How do I know, I had to upgrade a couple fuel lines on my Merc (outboard) to ethanol resistant stuff when they started putting that **** in the fuel.