Once the body filler had cured, I sanded with 60-grit paper, and then applied a skimming coat of glazing putty, which might have been overkill since the bedliner spray will cover most sanding scratches.
In order to make my life easier, I also tagged some of the vacuum hoses that were in my way. This will allow me to mask them properly and gain ample room to spray the firewall.
Bondo® Glass has reinforced fiberglass strands and is easy to use, although you only get a few minutes of working time, so working in small sections is the best approach. You just have to make sure the filler and the hardener are mixed thoroughly.
The filler creates more work, but it will make a huge difference when it's painted and all the cracks will be gone. I also used it to cover a couple of screw holes for an even cleaner look.
Originally I was going to replace all the grommets, but I think that won't be necessary as everything should blend in nicely when painted with bedliner spray.
Having said that, I plan to use new hardware, and since I will clean as much of the wiring as possible, I may choose to leave some of it exposed which, I feel, will provide a nice contrast.
Thanks for following my '76 Vette Blog, and stay tuned for Part 4.
Product Links... (#sponsored)
• Bondo Glazing Spot Putty | 16 oz.
• Dupli-Color Truck Bed Coating Paint | 16.5 oz. 2-pack