Restoration Sheetmetal Fitment Tips

Everyone wants NOS sheetmetal, but unless you’re made of money, new old stock panels are cost prohibitive for most musclecar restoration projects. Reproduction sheetmetal is an affordable alternative, but it often requires a fair amount of finagling to wrestle into place. Although the tooling used to manufacture aftermarket panels has resulted in dramatically improved fitment in recent years, some trimming and gentle massaging of the sheetmetal is usually necessary to achieve tight body gaps and perfect fitment. Here’s how to do it.  

 1) A very common scenario when performing sheetmetal repair is installing an aftermarket quarter-panel while keeping an original door. In this case, it’s imperative to pre-fit the door by aligning it door with the existing quarter-panel and fender.  Fit as many panels as possible, taking note of the shim and hinge placement. This probably won’t be the final location of the door, but it will give you a great starting point for the new quarter. When fitting panels, make sure the weatherstripping is in place, as this will ensure you have enough room for the door to close.

 2) After removing the old quarter-panel and cleaning up welds, mock it in place to see how closely it aligns with the original door and trunk. Some trimming will be necessary to acheive the best fit possible.

 3) Once the new quarter-panel has been wrestled into place, chances are the gaps at the door and trunk will not be within an acceptable range. Move the panel around to minimize the disparity in gaps as much as possible. Until all final adjustments have been made, keep the quarter-panel in position with clamps or self-tapping screws.

 4) After every attempt has been made to achieve a quality fit, it’s time to modify the sheetmetal.  Door-to-quarter edges are the most common. If the gap is too small, use a 3/32-inch cutoff wheel to remove roughly 1/8-inch of metal from the edge of the quarter-panel. Once cut, lightly tap the edge backwards. If it’s necessary to remove more metal, re-cut the quarter-panel along the same line. Repeat this process as many times as necessary to obtain an even 3/16- to ¼-inch gap. Use small tack welds to re-weld the gap and grind them smooth.

 sheetmetal body gap too small


sheetmetal body gap too small

5) If the panel gap is too big, make the same cut but this time use a chisel or screwdriver to draw the quarter-panel forward.  When the door edge gap is even with the door, use welding rod to fill the opening that has just been cut. Welding rod is available in 3/32- and 1/16-inch sticks, and it can easily be bent to match the contour of the quarter-panel. In sections where the opening tapers, grind the welding rod to a taper and tack it into place. Next, double check  the gap and weld it in solid, and grind it smooth.

 sheetmetal body gap too big large

sheetmetal filler rod

6) These same techniques can be used to push the quarter-panel or to pull it outward if necessary. Modifications are sometimes needed around the windows, trunk lids, valances and any other adjacent panel, but remember to make sure to align the panel as best as possible before making any cuts.