Between the factory holes and the holes put there by previous owners, the firewall is close to Swiss cheese.
I started cutting out filler pieces and welding them in. Tedious work, late in the day, hot, and I was still working faster than my compressor. Only got five holes filled, three with filler pieces and two backed by copper. I also got the rosette welds put in on the accelerator pedal support.
I also will have to determine what to do about the firewall pad as I realized some of the holes are for mounting it.
I had used a plumb bob to make a line on the floor from the front edge of the dash. Today I did the same thing with the front edge of the seat. The right side is about 5/8" ahead of the left side. I laid out some new hole locations. I will post photos when I drill the holes and re-install the seat.
In addition to the seat being removed, the engine, transmission, MC, booster, pedal assembly, steering column, and dash cross tube were also removed to make room for welding the firewall and toe board.
Since the steering column location is final, the sheet metal in the toe board where the column is located was finish welded. The hole for the original brake pedal was also filled as was the hole for the carpet pin which interfered with the lower column mount. (just to the right of the far left seam)
The engine was re-installed so the gas pedal would be in the (almost) final location.
After installing the engine, the booster and master cylinder were installed. It is amazing how far the MC extends into the engine compartment.
The pedal mount to square tube cross bar was tacked in place. The pedal was attached to the clevis. The pedal location is acceptable and the MC bottoms out before the pedal hits the firewall.
I may take a pie cut out of the pedal so that I can kick the clevis mount toward the rear. The mount goes past center before mid travel. It might provide better performance if it hit center at mid-travel.
After some research, I determined the pedal ratio to be 6.5:1. Not only did this cause excess pedal travel, it should have made the pedal very touchy if I had left it that way. I decided to modify the assembly to achieve an approx. 4.5:1 ratio. Moving the clevis mounting hole down by 7/8" would achieve this.
In order to maintain the alignment of the rod to the booster, I had to move the upper mount up. I thought about cutting the whole channel off the firewall plate, but I decided opening the top would be better. I must admit, I was beginning to think that the smart money would have been to buy a pile of steel and build it from scratch. But I was already on my way, so cut, heat, bend, and drill.
Once I am sure this is the fix, I will weld a section of rectangular tubing to the "ears" created in this mod.
I also had to cut 3/8" off the clevis and a matching amount off the booster rod.
The pedal bracket was bolted back in the car and a hole saw was used to make the push rod hole. The booster was installed, verifying clearance of the new recess. After a frustrating session of trying to set the pedal location and travel, I called it a night.