To install the master and starter relays to the firewall, I had to make this small doubler.

After measuring out the exact location of the relays, I could matchdrill the doubler to the firewall.

I also had to fabricate two small copperbars that connects the master relay to the starter relay.
Here they are temperarily installed. The doubler has not been riveted yet, as it needs a shot of primer first.

I also marked the location of the cabin heatbox valve.