When building a custom vehicle, it's the little things that matter. Often enough, these items are easy to overlook or even ignore. However, when all the little details are tallied up, they can dictate whether you have a show-winner or an also-ran. Take, for example, this 1971 Monte Carlo firewall. It's a basic GM A-body, and all the firewalls look the same. The plans for this firewall include subtle smoothing. We didn't go all out and make it as flat as a tabletop; that would be too boring to look at. Armed with a welder, grinder, body hammers, and body filler, a clean-looking firewall that retains the OE look can be easy enough to do. This Monte Carlo was last seen on our pages about a year ago, and now it's nearly ready for paint. We followed along as Harrison Ortis of Harrison Restorations (Upland, California) ironed it out. It only took a few days to do, but the results speak for themselves. The humble GM A-body firewall. Even when the hood is opened, it's only partially visible. Still, a smoothed firewall can add greatly to a vehicle's underhood appearance and can mean the difference between finishing First and Second in a car show. From the production line, the firewalls are utilitarian in purpose, filled with bumps, dips, wrinkles, and body caulking.The humble GM A-body firewall. Even when the hood is opened, it's only partially visible. The area that will receive most of our attention is where the firewall and cowl vent pieces are joined together. Spot welds and body caulking are what keep it together, but they don't look all that great. The first order of business is to work over this bare metal edge.The area that will receive most of our attention is where the firewall and cowl vent piece The generous amounts of body caulking applied at the factory are removed with a hammer and chisel.The generous amounts of body caulking applied at the factory are removed with a hammer and The residue of the caulking is ground out with an air grinder. The goal here is to clean it all the way down to the bare metal.The residue of the caulking is ground out with an air grinder. The goal here is to clean i A final photo here shows how clean the joint is before we start working it over. The goal is to roll the lip over. First, a body hammer is used to fold the lip up along the entire leading edge.The goal is to roll the lip over. First, a body hammer is used to fold the lip up along th Once the edge is folded up, a hammer and dolly are used to fold it down over itself and pound it into place.Once the edge is folded up, a hammer and dolly are used to fold it down over itself and po Here is the final result of the rolled lip. The sharp edge from the factory is now gone, but we are not done yet.Here is the final result of the rolled lip. The sharp edge from the factory is now gone, b The entire seam is now tacked into place with the welder. Even though the metal is thicker here, we are still careful not to apply too much heat and warp it. Everything is tack-filled until a solid, seamless line is achieved.Even though the metal is thicker here, we are still careful not to apply too much heat and Afterward, all the welds are ground down and smoothed as much as possible. The dimples on the firewall and spot welds that were not accessible with a hammer and dolly were all tack-filled with the welder.The dimples on the firewall and spot welds that were not accessible with a hammer and doll The firewall (from the factory) is filled with high and low spots. We employed a hammer and dolly to flatten them out as much as possible without stretching the metal.The firewall (from the factory) is filled with high and low spots. We employed a hammer an Once again, the grinder is put to work grinding down the tack welds on the firewall. Despite our best efforts with the welder and hammer and dolly, some areas will still be impossible to get to because of the double steel wall and vent passages. Most of the effort put into the firewall is going to be in the visible areas. Our efforts would be wasted in placed that are going to be covered by the inner and outer fenders or areas where the bellhousing is.Despite our best efforts with the welder and hammer and dolly, some areas will still be im Evercoat Extreme body filler was used to level off all the low spots on the firewall and cowl vent panel. After the filler set up, we sanded a great deal of it back off. We left just enough to smooth it all out.Evercoat Extreme body filler was used to level off all the low spots on the firewall and c Areas where we could use a DA sander sped things up nicely. The rest of the sanding was good old-fashioned, elbow grease. We used 80-grit paper with both the sander and manually.Areas where we could use a DA sander sped things up nicely. The rest of the sanding was go Once all the sanding was done, the vehicle was rolled into the paint booth, and the firewall and, of course, the rest of the bare metal was shot in etching primer.Once all the sanding was done, the vehicle was rolled into the paint booth, and the firewa About 20 minutes after the etching primer dried, the high-fill PCL poly primer is sprayed over the entire vehicle. This primer is perfect for filling up to 80-grit sanding scratches.About 20 minutes after the etching primer dried, the high-fill PCL poly primer is sprayed Two days later, after the primer had finished drying and "out gassing," the fun part of the job began. This is otherwise known as wet sanding. The reason for wet sanding is to level off the primer surface. A level primer surface without any type of texture will help the paint and clear lay flat with very little texture.Two days later, after the primer had finished drying and "out gassing," the fun part of th While the car is being dried off outside, inside the paint booth the PPG DBC Copper Head pearl basecoat is being mixed at a 1:1 ratio. This color was a one-year-only application on the '05 Dodge Viper. The copper color should look great on this Monte Carlo. The PPG was purchased at El Monte Paint in Rancho Cucamonga, Calif.While the car is being dried off outside, inside the paint booth the PPG DBC Copper Head p Three coats of PPG Copper Head were spayed onto the firewall. Here is the final shot of the semi-smoothed firewall. Imagine it with the inner and outer fenders, A/C delete panel, master cylinder and booster, windshield wiper motor, etc.Here is the final shot of the semi-smoothed firewall. Imagine it with the inner and outer A few days of work adds a subtle touch to the underhood look of any vehicle. As for the rest of the story on this Monte Carlo, we will have the paint and body article on the Super Chevy website (www.superchevy.com) once it has been block-sanded.A few days of work adds a subtle touch to the underhood look of any vehicle. As for the re SOURCES El Monte Auto Paint Harrison Restorations By Mike Harrington Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
