Heavy-Duty Battery Transition Period

At the start of '67 model year production, the RPO battery for all Mustangs, including the Mustang-based Shelby GT, was the Group 22 45A battery.

The exception was cars equipped with the FE big block mated to a C-6 automatic transmission.

For '67 the FE included the 390 CID, and, in the case of a Shelby GT 500 unit, the 428-8V Special Interceptor.

Dimensionally, both batteries share the same height of 8.95". The Group 22 is 9.42" long and weighs 30 lbs, while the Group 24 is 10.75" long and weighs 34 lbs.  

The Heavy-Duty (HD) battery option is indicated by a value of "1" in column 63 of the 80-column Ford Computer Record (FCR). The FCR can be found atop a Deluxe Marti Report.

The HD (Group 24F, 55Ah) battery was included as standard equipment on Mustangs equipped with the FE 390 and an automatic transmission.

When included as standard equipment, Column 63 would not have a value of "1" despite the car receiving the Group 24 55Ah HD battery. The Shelby GT 500 units with 428-8V Special Interceptor and C6 automatic transmission followed suit, and would have automatically received the G24 55Ah HD battery (and Column 63 of the computer record would have been blank).

Beginning with DSO 2579, all Shelby GT 350 and GT 500 4-speed units were specifically requisitioned with the "55Ah Battery" on this special order forms (it wasn't requested on GT500+auto for the reason stated above).

DSO 2579 was canceled. The earliest car on DSO 2580 was built at the San Jose plant on 3/30/1967.

However, the SRG's analysis of Ford Computer Records indicates that the HD batteries started getting added to some cars that were built as early as December 12, 1966.

By February 2, 1967, Ford computer records indicate that all Shelby GT 350 and GT 500 units built at the San Jose assembly plant received the Heavy-Duty (Group 24F) battery option.

The data associated with this page displays cars built between December 1, 1966, and February 1, 1967, whose battery type has been confirmed by a Ford Computer Record. We are still collecting more data (Marti Reports) in an attempt to identify any patterns during this transitional period. GT 500 Automatic cars have been excluded from this query since all of those received the HD battery as standard equipment.

We are not sure if this is a running change that affected only Shelby units or all Mustangs/Cougars, nor do we know if this was limited to the San Jose assembly plant.

The pattern does not appear to conform to specific DSOs. For example, DSOs 2525, 2528, and 2551 have mixed results.

The pattern does not appear to follow specific package codes, but we may see the HD battery implemented at different times depending on the car's package code.

Perhaps some of the early cars equipped with an HD battery could be related to mistakes or a substitution due to product unavailability?

The only way to fully conclude this research would to to gain access to the battery column value for the cars in this time period. Those could only come from Ford or Marti, and, unfortunately, neither of them appear willing to help.
 
 
See Also

• Ford Domestic Special Orders (DSOs)
• Production Gantt Charts - Ford San Jose