I used a filler door from a 1980 F-100 and had to trim it very tight around the recessed door pocket to make it work. A '78 or '79 F100, 150, 250 Truck or Bronco would be easier since the curve of the bed matches ours perfectly.
This was the initial trimming to square it up. I eventually trimmed it a second time when I realized the curve didn't match our beds:
Now onto the scary part - cutting a hole in an otherwise immaculate short bed. I ended up measuring about 53 times, plus figuring out how the hose would route to the tank:
Here you can see the final trim on the recessed piece. Had to make sure it was exactly in the center of the curve or crown on the bedside:
Using a 4" cut-off wheel, just took my time and trimmed it square. You can see the paint blistering where it got hot:
No turning back now:
Sanded and deburred the edges for a clean weld:
New filler panel positioned in and clamped tight:
Weld in very small sections doing a spot here and spot there. Tedious but very important:
Finished welding:
My favorite part, making it look pretty. 80 grit flap disc on an angle grinder:
Temporary fit of door. It will be flush when it's bolted in and the rubber bumpers are in. After pic was taken, I smoothed everything over again with an air sander to minimize any body filler:
Next part is the basket holding the filler neck on the inside. I'm making my own out of 22 ga. steel and using a filler neck from a 1998 Crown Vic. It has a 1" diameter fill tube which will allow the fuel hose to run directly to the tank with a mild s-turn and fit under the bed/over the frame rail without any kinking.
Hope this helps some folks in this same area.
