Cowboy - there was optional AC available in the cars then, but not the trucks - that's no doubt an old 'retrofit', possibly using the car stuff, but there's always been '3rd party' units available - hafta check into wether it's worth rebuilding w/ someone local, re the freon situation - illegal now, and can't be mixed w/ the new stuff, so requires purging the system completely, and the newer version may not work in yer old unit
Bill