Firewall Modifications

Now that I feel like we have brought the frame of my 37 back to life I can start to think about other parts of my project. While I can't get to far into some of the body modifications with the cab off of the frame there are others I can go a head with. After going over the cab and knowing what I wanted to change on it I decided to start on the firewall. I debated on this for a little while. A small block Chevy is supposed to fit without modifications to the firewall. Yea, and one size fits all. I decided to go ahead and assume it will fit.

For 1937 the a battery box was added to the firewall on the passenger side. Not only was the battery box added, the whole firewall was a new stamping. I had been tossing around the idea of how to best remove the battery box when I was offered what ever I needed from a butchered 1936 cab. While it had already been trimmed out for a modern V8 and trans there was plenty left for me to work with. As you can see I brought home what I needed. The hole in the middle of the raised X was the only draw back, it will be filled with a section from the drivers side.

After looking over everything I decided I needed to cut out the battery box first before I could fit anything up and trim things to size. I had to cut the hole a little wider than I planned to include the battery hold down holes. At the top I wanted to stay below the raised W but needed to be above bend to include all of the battery tray. At the bottom I had plenty of room except in the center where the donor firewall was trimmed for transmission clearance.

Once the battery tray was removed the donor firewall was trimmed oversize for a trial fit. The new section was then fit on top of the old firewall covering the large hole.

There are several points that need to line up to pull this modification off. The center recess needs to line up at the top and side, the two horizontal bends and the raised M needs to line to line up. On the stock 37 firewall the M bead stops just before the right edge of the battery tray.

Once I was satisfied I clamped the new section in place. I missed cutting the 36 firewall wide enough by a small amount on the left side. I would have been all right except for the pocket for the holddown on the 37 firewall at this location.

From here both the 37 firewall and the donor section took turns getting trimmed for a good fit. If the 36 firewall had not been trimmed in the past for clearance all my cuts would have been pretty straight. Since it was I had to match the lower right corners with a curved cut.

Once I was satisfied with the fit it was time to tack weld the firewall together. It was also time to start running into problems. My welder didn't want to cooperate with me. If I held the trigger in just the right spot I could get it to work, sometimes.

I finally got a few ugly spot welds on there to hold it together but I was hoping to finish this part of the firewall up and impress anybody that came over to check out the progress. Hey, check out what I did to the firewall, and when they look and ask what did you do, you know you pulled it off.

This is one of those jobs that if you didn't know what was there before it just looks stock. Now I need to get my welder fixed and finish the job and weld up the rest of those unneeded holes.

I'm sure there will be some more modifications to the lower center firewall but that will have to wait until the can is sitting on the frame with the motor and transmission in place.

I have my welder working again, not great but it is working. I have the new section of firewall welded in place and the welds ground down. The next step was to fill in the round hole located right in the middle of the raised X. I used the other side of 1936 firewall to cut out this section. I trimmed the filler piece to match the round hole and welded it in place. I made a mistake here that I found out while grinding the welds down. It was pretty tight grinding the welds down without getting the disk into some other raised section. I should have welded it from the back side or trimmed the original hole larger. Live and learn. A small amount of filler will clean up these small areas at a latter date.

Fill in a few more holes and I can move on to the next area.