Building a heater into rear defroster blower hose

Just a reminder, that figures up around 200-250 watts at 12-14V is one HELL of a lot of current, approaching 20A. Your old Mopar ammeter/ bulkhead circuit may not/ probably won't put up with that on top of the fuel pump, fans, stereo, heater, lights, etc etc etc that is already in use

And of course you'll need a nice big high output alternator.

Ford / Lincoln used to make a deal where the defroster was fed directly off the 3 phase stator output, which did not "go through" the rest of the system, fed the defroster directly. I have no idea how reliable they were................