Hello, I am trying to determine the correct radiator for a Metuchen built 66 Mustang GT with automatic transmission, A/C, power steering, and date of October 28, 1965. I have attempted to find my answer through the site but possibly missed something. I am having difficulty in finding the differences with the various suffixes (G1, M1, M2, Y1, Z1, Z2, and etc.). Would anyone have a book or other resource you would recommend or know the specific radiator part number that I need? I believe the first part of the number needed would be C4ZE-8005 but I could be wrong. I would really like to understand the various suffixes. My research of suffixes points to a mixture of San Jose versus Metuchen and automatic versus manual. I appreciate your help.