When you are on the lookout for a replacement underdash harness for your 1970 Mustang, be aware that there are several different ones that were produced depending on certain options, body types, and date of manufacture. Below is a list of those harnesses that were used.
 
Body Codes Harnesses
63A - Sportsroof Standard Interior
63B - Sportsroof Deluxe Interior
63C - Mach 1
76A - Convertible Standard Interior
65A - Coupe Standard Interior
65B - Coupe Deluxe Interior
65E - Grande
76B - Convertible Deluxe Interior
- 63A,B,65,76 without AC without tach
- 63A,B,65,76 without AC with tach before 11/1/69
- 63A,B,65,76,without AC with tach after 11/1/69
- 63A,B,65,76 with AC without tach before 11/1/69
- 63A,B,65,76,with AC without tach after 11/1/69
- 63C without tach before 11/1/69
- 63C without tach after 11/1/69
- 63C with tach before 11/1/69
- 63C with tach after 11/1/69