Being from Texas we don't worry a millisecond about heaters but know about a/c units. The cheapest on the market I know of is from Lucky's Rod and Kustom in Ennis, Texas. You can get a turn key heat and cool unit for $600 or as I did for my 37 Buick just the under dash part for $200. It only hangs down about 2" so not in the way of anything.
