This grommet is 70/57.5mm. Federal models up to 1984. If you need the complete fuel tank reseal kit - here is the 2WD Fuel Tank Reseal Kit with Rubber Cross Over Pipe & Aluminum Fittings or the 2WD Fuel Tank Reseal Kit with Plastic Pipe & Fittings. 

How to Determine the Difference Between California and Federal Fuel Tank Models. 
Under the front passenger wheel, you can see the fuel pipe that leads to the tank. On California models (Pictured), you can see a decrease in the tube size (from a circumference of 7.5" down to 5") right after the filler opening. In contrast, in federal models, the tube stays at a constant circumference of 7.5" from the filler opening to the tank. If the filler neck tapers down, you need the 57.5/50mm grommet. If it stays the same circumference, you need the 70/57.5mm grommet.

Ref ID: 251201139