My 46 Special DeLuxe Plymouth came with the MoPar Deluxe Model 36 heater. But there is also a knock-out for a round hole in the dash board (firewall) that I assume was for some type of fresh air heater option. Has anyone ever seen one installed? Since my car was originally sold in Oklahoma (where it was always tagged until I hauled it to Ohio a few years back), I don't know if it had a heater from the start, or if it was installed later on. That round hole knock-out (about 3" in diameter, I think, w/o going out & measuring it) was a bit buggered up, so I did a fiberglass patch over it back in the early 80's. So it wouldn't be easy for me to put something through there on mine, but it's mostly a curiosity.
What other model heaters have you all seen in 'original' P15s?