These large 3 1/4" O.D. fuel caps are just like the originals. Designed to be painted.
Please don't go by the year but use the guide to identify the right cap. Some Broncos may even have one of each.
CHOOSE THE CORRECT CAP
Earlier year models have a different sized fill neck and this one will not fit those models. This cap is represented by the cap on the right in the 2nd photo above and was designed for the Late 70 through 76 Bronco and has a longer reach into the filler neck.
The cap on the left is the 66-Early 70 (part #9764)
Make sure you order the correct one for your Bronco. Because many Broncos have been taken apart and put together with parts from various years it's better for you to look at your old cap to determine which version you need.