i'm still working on this greasy 66 car. scheduled build date of august 31 dearborn. i removed the heater to replace the blower motor. it was original with a C2 # and a date of may 1965. three wire unit. how far into 66 production did these carryover? the owner went by the catalog and brought me a 2-wire motor. catalogs say changeover was in april 65.......comments please.