Mark a point 2 inches past the B pillar window vertical frame and cut down through the frame infrastructure beam support. This cut must miss the B pillar support itself and leave intact the plastic clip just past the B pillar used to hold the rear side panel trim.
2. B pillar/quarter panel cut
Working back towards the B pillar, trim the exterior metal skin flush with the window frame and stop at the corner (see arrow in photo below). Then cut the exterior quarter panel skin straight down flush with the B pillar support ending 1.5″ above the bottom rocker panel.
Next follow the horizontal line 1.5″ above the rocker panel and terminate at the fender curve.
3. Fender trim
Trimming the fender involves a number of smaller cuts.
Follow the fender curve up past eight bolt holes, ending past the seat belt bolt plate. Make a 90-degree turn and cut back to the double flange above the fender body. Then continue along the double flange back towards the rear end cut line.
Trim off the small pieces left on the outside of the fender, like the mount area for the filler lid actuator, until the fender surface is relatively smooth. Coat all cut surfaces with a rust-preventive primer.
Take extra precautions when cutting to avoid damage to the gas filler and emission assemblies on the right side.
4. Fiberglass quarter panel rough fit
After making all the metal cuts (except for the final roof cut at this point), you can do a rough initial fit of the fiberglass quarter panels. This provides a quality check to make sure there are no remaining bits that conflict with the fiberglass and need to be taken off. The seat belt bolt plate will need to be bent down a little to clear the fiberglass shell.
Note that the section around the B pillar/door edge probably doesn’t fit well (more trimming of both metal and fiberglass will be required) but this will be addressed later.