Assembled the left and right forward rib subassemblies and final drilled the parts #30. Disassembled and deburred the holes and final drilled the screw holes and nutplate rivet holes. Deburred and then dimpled as called out. Smoothed the edges and countersunk the stiffeners to go against the firewall (and the left one to go against the recess), Clecoed all the parts back together and to the firewall. Clecoed the fuel selector mount in place and assembled the scat tube parts and clecoed the flanges in place. Final drilled those parts and dimpled the fuel selector mount and rib subassemblies. Deburred the fuel selector mount and clecoed it back in place.
NB: most of my time today was spent chopping a path through the ice in front of the hangar man door. I was at the hangar over 5 hours; when I wasn't actually chopping ice, I had a torpedo heater softening it up while I worked on the RV.