The oldest one I could find in a local yard was an 87. It mounted directly in the cowl as opposed to in the heater box. It also had I think 5 or 6 terminals that connected to a single molded plug. Mine has a 3 terminal plug and one single one. I should just pick one of them up from the yard and try it just for giggles. Pop my terminals out of the plug and to make a newer one work. A guy on a facebook group has also success soldering in a new diode on his with good results. Maybe I'm just being a cheapskate, but $80-100+ for an NOS one is a hard pill to swallow for me.