While "removing firewalls" will have a totally different meaning to computer geeks, to us gearhead types it will always have connotations of making space for a bigger motor, because if the firewall is in the way, that's usually the reason why, not to mention a new, shaved firewall looks much better. Direct Sheetmetal manufactures a recessed firewall for '55-'59 Chevrolet and GMC trucks in addition to many others, which not only offers improved engine clearance but also cleans up the firewall without having to weld plugs into the numerous holes in the stocker.
When KA Custom in Huntington Beach, California, told us they were about to install such a piece, we headed straight over, though it soon became apparent that there'd be a little more work involved than first thought, as the cab the customer supplied was a little worse for wear, and had been involved in a substantial collision at some point in its life. Now mounted on a straight frame, the firewall and right side of the cab was bent, twisted, and generally a mess. However, the mounting holes in the floorpan were still in alignment (it fit the chassis perfectly) so even though some of the floor was kinked, it wouldn't take much to return it to its rightful shape, especially given we'd be cutting much of the damaged sheetmetal out.
Kevin Francis at KA Custom had originally intended to reuse the lower firewall section, but after inspecting the cab when it arrived, and realizing what would have to be done to repair it, he opted to fabricate his own lower piece, which we'll show you in the second installment of this story. Meanwhile, let's get on with it, and straighten out that cab.
Here's our firewall recipient,...
Here's our firewall recipient, a rust-free '55-'59 Chevy Big-Window cab that had received some crash damage sometime in the past, then was swapped onto this frame.
The cab didn't look bad at...
The cab didn't look bad at first, but subsequent inspection revealed it had been hit hard, pushing the motor into the firewall and putting a crease in the front of the cowl, above where we'll be replacing metal. The A post closing panel behind the front fender had also taken a hefty smack and would require replacement. Pushing the firewall back bent the floor, but the good news was that the door apertures measured the same so the A post wasn't pushed back.
Using a torch to soften it,...
Using a torch to soften it, all undercoating that covered spot welds or would be in the way of plasma cutting was scraped off.
The top section of the firewall...
The top section of the firewall was removed with a plasma cutter, around the upper and side flanges and across just below where the vertical part of the firewall bends and becomes the floorboard. A grinder and cutting disc would work just as well but take longer.
Wearing gloves--irrespective...
Wearing gloves--irrespective of the heat generated by the plasma cutter, the edges of steel sheet are sharp--Kevin removed the old section of firewall. You can see from the section that remains on the cab just how far back the firewall had been pushed in the center.
The old and the new. No comparison...
The old and the new. No comparison really, is there?