Rebuilt 69 & Newer Dual Field 65 Amp Alternator, (Square Back Style), with Single Groove Pulley. Dual Field Alternators were first introduced in 1969 for the Imperials only, along with the First Electronic Voltage Regulator. In 1970 all Mopars received the Dual Field Alternator. These New Dual Fields all had the appearance of the earlier 60-69 Single Fields until Late 1972 Production. Starting from Late 1972, the Dual Field Alternator received a new Diode Design that changed the appearance of the back half of the Alternator, which is how it received it’s Lingo Name, “Square Back”.