I ordered a new left side torque box from Classic Enterprises .
Classic makes high quality replacement sheet metal parts for Studebakers and other classic cars. Their Avanti torque boxes are their own 5 piece design which makes it possible to replace them without damaging the fiberglass rocker panels or having to lift the body all the way off the frame. Other manufacturers make a one piece box which most likely will work fine if you are doing a body off restoration.
With the Classic torque boxes you end up with replacements that are stronger than the originals due to the heavier gauge metal used and the engineering of the kit.
The parts arrived soon after I placed the phone order...
The main section is actually two pieces. The short front part is attached to the longer rear part with four screws. These will be disassembled for installation, then reassembled and welded together once in position on the car.
The other long piece is the part that will attach to the portion of the old rocker rail which remains in the car.
The other two fabricated sheet metal parts are the roll bar bulkhead and the end cap.
Also included are all the fasteners that are needed, adhesive/sealant, and instructions.
My friend Paul had graciously agreed to help with the installation. Neither Paul nor I had replaced the torque boxes in an Avanti, but Paul has had years of experience doing restorations and building hot rods and I was good at passing tools! We both reviewed the instructions that came with the torque box and an informative article from the Avanti Magazine by Chris Altenburg and Marty Burns.