1938 - 1939 - 1940 Dash board differences, are they interchangable.

[53 Chevy5]

Does anyone ever put a second evaporator in the back, with a second fan?

I think it can be done without too much trouble. All semis' have a separate rear A/C and heater units in the sleeper and so did both of the vans I had. There is a separate expansion valve/ orifice tube for both units and I think they shared the dryer. I think the only difference was you needed a larger pump. When I was looking at new A4 pumps for my 53 there was the heavy pump for rear A/C option. As for the plumbing you need to double check but it seems to me they just tee off the high and low side lines for the rear. At least I know I've seen tees' capped off when the sleeper is removed.