Taillight Fuel Filler Installation for 1973-⁠1991 Chevy Squarebody Trucks

Relocating the fuel filler behind the taillight on a 1973-⁠1991 Chevy or GMC Squarebody — what comes on the cutting template, how to print it so it is the right size, and the full video walkthrough.

A squarebody fuel filler swap hides the gas cap behind the taillight and leaves the bedside smooth. The hidden filler kit for 1973-⁠91 Squarebody beds moves the filler out of the bedside and puts it behind the taillight, so the side of the truck stays clean. The cut is the part that has to be right, and it is made from the printed template rather than by eye.

What is on the template

The printable template sheet carries four pieces, each labelled:

• Driver side inner
• Driver side outer
• Passenger side outer
• Passenger side inner

Only one side gets cut on a given truck, so identify which side your filler is going on and set the other two pieces aside before you start marking anything.

Printing the Squarebody fuel filler template

1. First, print at 100%. Turn off “fit to page” and any scaling in your printer dialog. A template printed at 97% looks fine on paper and cuts a hole that will not line up.
2. Measure before you cut. Check the printed sheet against the part itself before it goes anywhere near the truck.
3. Finally, cut the pieces out and hold them up to the bedside to confirm the position looks right.

Installation video

The full install walkthrough for the Squarebody taillight fuel filler. Watch it on YouTube if you want it full screen.

Use fuel-rated hose and clamps only, and make sure the tank keeps its own vent. The same kit exists for the earlier trucks, and the 1967-⁠72 fuel filler guide covers that install. Relocating the filler is usually done alongside stone shields and billet door hardware — those and the rest of the range are in our 73-⁠87 Squarebody truck parts collection.