My original plan was to move over the whole front of the car in one piece. The issue was in how to replace the firewall if I didn’t separate the engine bay from the dash and cowl. Ultimately, I decided to separate the engine bay and do it in 2 moves. Once I got the frame rails off, I saw why it was welded along the seam and not plug welds, which changed all my plans. I was still on track to move the dash, cowl, and A pillars as a unit, so I got to work.

I started by making some braces that will effectively be the measuring stick to get the A pillars back in place on the new floor, relative to the B pillars.

As I started cutting, I found that no paint or primer was used to cover the internals of the torque box, and this is not original. The upper torque box plate wasn’t welded to the floor either. Notice the popcorn welds along the frame rail and floor support. That’s a clue that I didn’t understand until I got the rails off.

On the up side, this was a lot of fun to tear apart with the plasma cutter.

The floor support slots are supposed to be welded to the frame rails with 2 rows of welds down the side and bottom, either from the factory or as a repair. These appeared to be welded only with some junk popcorn along the edge of the floor support. Once I got them off and looked inside, I see what the issue is. There is no metal to plug weld to on the sides. I am pretty sure this thing would break in half on the first solid bump it hit. That changed my plan. Now I need new frame rails. I will push this decision off a bit, but I will either get all the parts, or get one piece assembled left and right complete shock towers. Either way, its time for new metal. But for now, I continue with the original plan and continue cutting the second block of parts off.

More cutting and the second sub assembly is off. There is no end of sand that keeps coming out of this thing. I’m glad I did this if for no other reason that to get all the sand out. With it off, I still have to clean up all the parts I cut off, like the firewall. I also need to make a plan on how to deal with the kick panels since they wont come off clean without taking this all apart. I am going to have to cut some percentage of the original out, and graft in the new section.

With the assembly cleaned up and all the scrap pieces removed, I put it in place and test it out. It dropped right in and fit just fine.

One kick panel cut and clamped in place. I left the top third of the kick panel on the back of the A pillar due to how it attaches and is unreachable without total disassembly. I butt welded the new part in. I test fit it to make sure it lines up right. There is a notch on the front where it interacts with the rocker panel flange that I had to open up some, but other than that, it worked well. After the driver side, I did the same on the passenger side.

I did not weld the bottom or the top of the kick panel in yet. I will do that when I weld in the firewall. In order to fit the firewall, I needed to cut out the area where the inner rocker is. The firewall is a universal piece that is made to fit all 3 body styles. Since the convertible has the inner rocker, it has to be modified to fit. It’s a bit tricky since it is on an angle, but with a little math and multiple tries, I got it in for a test fitting.

With the firewall, I need to install the upper or inner plate from the torque box. This goes in between the firewall and the convertible rocker panel, with the other part going on after the frame rail is welded in.

It took several cuts, and I got the angle in the wrong place, but it will work. I ended up folding the angle tab back in to fill the gap and just using the top and side tabs. You can see both the torque box and firewall tabs are overlapping.

At this point, I didn’t take pictures, but I welded in the A pillar on the rocker panel. Prior this, I did fit the passenger door to make sure the spacing was correct, and it was fine. With that welded in, I am able to remove the support frames I fabricated, allowing me room to weld the inside of the firewall.

To weld the firewall and kick panels to the cowl, I bought a pinch welder from Harbor Freight. For this, the metal has to be clean with no primer or e-coating in order for it to get a good contact. I chose this approach for the cowl since normally the cowl would get built on top of the firewall and I didn’t want to weld up from the bottom. With the cowl being a perimeter flange weld, its a good candidate for this approach. My only concern was that it was 3 layers of 18-20 gauge sheet metal, but that ended up not being an issue.

I ground down the welds enough to keep from feeling them under foot. Probably didn’t need to with the carpet pad I plan on using, but it will look better when painted as well.

The last piece is re-drilling the export brace holes in the firewall. With the firewall centered and the flange contour aligned, the holes were about half an inch to the left. Since the cowl is original, I am keeping those holes to keep the brace aligned where it was previously since it worked. I just need to find my step bit. In the future, I also plan on welding in the heavier support bracket over the top.

Kick panels are welded in and this stage is done. Now on to building the engine bay while I avoid dealing with the quarter panels. I need to spend some quality time with the seam sealer at this point as well.