With my son home from University for the holidays, I had him draw up my proposed layout for the radio and intercom for the rear panel. The original radio was panel mounted fitting into a standard 3-1/8" instrument hole. A friend referred to the radio as an old "coffee grinder" style. It appears to have had radio and intercom functionality. See attached picture. I want to install a new radio in the same hole without cutting into the original panel. My plan is to use a Trig TY91 remote head radio with a Sigtronics Sport 200 intercom mounted underneath it. My plan is to mount them stacked on an insert mounted within the original 3-1/8" hole. See attached drawing of the layout.