I thought I had the parts for the upper firewall ready to go. I had already cut out and bent up the filler neck box, its forward side and doubler plate. I had also cut out the upper firewall outline and the windshield attach strap. Today, I started by drilling the hole pattern in the windshield attach strap. Then figured out that the ends of the slots at the bottom of the upper firewall are to be the tooling holes for the form block, so drilled there and filed to ovalize them until they matched the form block. The form block has a third tooling hole in the area that gets removed for the filler neck opening, so I drilled that into the sheet through the form block. Bolted the form block and backing block to either side of the sst sheet and started hammering. Removed the upper firewall from the form blocks and used the fluting pliers to bring it back to flat. Then tried fitting the strap. It didn't. Checked the angles and hand-bent some more angle into the firewall to get the strap to fit. It didn't. Figured maybe I'd bent too much, so I cleco clamped the center of the strap and the end and saw that the more bent portion is only near the ends. The vast majority of the center is around the 70 degrees or so. Got the angles adusted right, and drilled the strap to the firewall.
Strap fitted.
The other side.
The cut out. Used a dremel w/ cut-off wheel, then filed the edges.
