There was a time when repairing extensive rust damage on a Tri-Five Chevy or a GMC cab meant tracking down a good or at least better example of the necessary sheetmetal and then carefully cutting it out. From here the next step was to figure out how to gracefully graft it back onto the truck. Back in the '70s, when these trucks were 20 or so years old, it took a real metalman and a fair amount of luck to pull the job off successfully. Flash forward another 10 years or so and the pool of good replacement used tin has diminished considerably, and time has taken its toll on the number of good metalmen around.
That said, it would seem things in the 21st century should be pretty bleak, but that's not the case. To the contrary, there have been some major breakthroughs in the availability of good reproduction restoration parts and welding technology that make it easier for a DIYer to do a professional welding job. Notice we said restoration parts, not crash repair. Crash parts are usually cheap junk that fits poorly and devalues a truck, while restoration parts are intended to be undetectable from the original. The restoration parts Carmen Porca installed on his '57 Chevy big- window were sourced from Tucker's Classic Pickup Parts in Las Vegas, Nevada.
Installing the new parts started out much in the same way as the old days. The rusted pieces had to be carefully cut out of his cab. But before this could happen, it was absolutely necessary to weld a flat support strap into the doorjamb above the step (the running board in the cab) to eliminate any possibility of the cab springing (distorting) out of its original shape. Trust us, if you continued on page 66 fail to properly reinforce the cab and it springs out of shape, you will have a nightmare on your hands trying to pull it back into place.
Once the cab is reinforced correctly, the next step is to carefully cut out the rusted parts. The following steps involve determining the right sequence in which to install and weld in the Tucker's parts. This was done through a mock-up process, then tack welding them into place. The final welding was not completed until everything was double-checked for fit. As with any improvements to your truck, the key to success is patience and proper planning. So there you have it-take your time, think it out, and have fun!