Now, determining the position of the bottom flange. If this flange is not in the correct position, the rib could be too high (causing a bulge in the skin) or too low (causing a gap between the flange and the aluminum angle near the top of the firewall).

Hard to see, but bend marks have been carefully laid out.

Rib fits nicely.

Since the ribs are now correctly positioned 1/4" from the gooseneck arms, this little plate needs remade.

Here's a new one.