The firewall forward kit included an alternate air door and a push-pull control cable. I think most people mount this on the aft port gear tower but I have too much "stuff" inside the tower in just the wrong place to interfere with even one more cable.
I don't like my solution but it should work well and is sturdy. I fabricated two mirror image brackets from angle aluminum that are attached fore and aft on the port gear tower using two (each bracket) of the pan head screws that attach the inspection panel. The picture below shows the brackets and cable but the inspection panels are not installed.
The cable will extend forward and penetrate the firewall and then be routed to the sliding door on the snorkel. The brackets are now out in the shop being painted.
