[Woodnears]

It's simple but time consuming but basically I cut three strips of 18g a hair larger than the widest part. Measure in a few spots because the distance from the firewall to drop edge changes a bit. Use the longest measurement. I started at the passenger side and worked my way around tacking as I went. Use a sheet metal hammer to work the metal strips into shape as you go. The secret I found was too find a real thick new grinder wheel to grind the inside corner welds. It made a nice square grind.