All of the aftermarket sending units are garbage unless you need to go above 5/16" for some reason. Get an OEM sender on ebay or post a want ad here and restore it if needed. There's places you can mail it to for restoration such as here:
Fuel tank sending unit rebuild service
Usually all they need is a new float, which are cheap:
Amazon.com: Omix-Ada 17729.01 Fuel Tank Plastic Float: Automotive
-New sending units are linear, so your gas gauge won't function like an original unless you get one of those Meter Match devices to make it work remotely correctly:
Solution to Fuel Gauge/Sender Problems
-New sending units often will have an improperly adjusted pickup tube that won't get to the bottom of the tank. Hopefully you'll have the tank out of your car so you can inspect this and bend the pickup tube as needed. I had to bend mine a good 2-3" downwards it was so far off
-You will also most likely need to tweak the float arm so it travels the full range of motion and/or helps the gauge read remotely correctly, especially when below 1/2 tank
Regardless of which sending unit you use be sure to check for leaks. Most of the aftermarket lock rings, even the ones that come with a new gas tank, don't fit snug and will allow a leak. Use your OEM lock ring if you have it. A member on here sells them. You can also try this:
Fuel tank sending unit leaked - fixed
I have 1 on order and I will inspect it side-by-side with my OEM lock ring when it arrives.
