Editor’s note: Marcus Anghel is the owner of Anghel Restorations in Scottsdale, Arizona. His research into some of the less obvious Mustang parts has proven beneficial to other Mustang concours restorers, so we’re providing his article here about battery heat shields, which were commonly removed and thrown away at the first battery replacement.
The purpose of the battery heat shield, listed by Ford under the basic part number of 10A682, was to provide an extra layer of protection from the heat created in the engine compartment. It was believed that the constant heat being radiated to the battery case would affect battery life and cranking amps by causing electrolyte to boil over.
The shields were either installed without modification or were trimmed to fit the model and application.
The heat shield first appeared in the 1967 Mustangs and Cougars with the introduction of larger engine size options, including the 390 big-block. In certain applications, the air-conditioning option triggered the need for a battery heat shield due to the additional underhood heat. In general, documentation supports the use of the heat shield in most cases for high performance models and air-conditioned cars. The guide here shows what original shields look like and the differences between them.
The early battery heat shields from 1967 to 1969 have two different engineering numbers on the same shield. This is because the same molded part was used for more than one application by cutting and fitting to size. The shields were either installed without modification or were trimmed to fit the model and application. So for different model vehicles, the same heat shield could be used by simply cutting to fit. This was done by Ford to create model specific heat shields from one single molded part. The trimming was for different model vehicles and not related to the battery size being used.
There were many other battery heat shields used in different Ford models besides Mustang, including C6SB-A, C6SB-B, C7SB-A, C8SB-B, C8VB-A, D0VB-A, D2VB-A, and D2VB-B.
Rarely seen, this first version of the battery heat shield has two engineering numbers—C70B-10A682-A and C7ZB-10A682-A—molded on the inner face near the FoMoCo logo. This early version from late ’66 or early ’67 was molded in light grey plastic. It has not been determined if this shield was used in production models, but if so it was only for a very short period.
This second version is the most commonly found original battery heat shield in ’67 to very early ’70 Mustangs. Changes from the first version include a slightly increased height and the elimination of the top molded tab. Early versions seem to be molded in light grey plastic and later versions in a dark grey plastic. It has three molded engineering numbers: C7OB-10A682-B (113⁄8-inches uncut); C7ZB-10A682-B (9-inches cut), and C7ZB-10A682-A ( XXX’ed out).
When used in the Mustang or Cougar, the second version heat shield was trimmed (shown in bottom shield) to an overall length of 9-inches (regardless of battery size) and the bottom edge of the shorter side was cut.
Here you can see where the bottom of the second version shield was trimmed for the battery case’s lower edge.
For early ’70 to ’73 production, Ford manufactured a third version of the battery heat shield, with molded engineering number D0OB-10A682-A, for a one-size-fits-all application to eliminate the need to cut and fit. The ’70 Mustang assembly manual drawing dated August 29, 1969, shows this shield replacing the previous version.
Changes in the design of the front radiator support area of the ’71-’73 Mustang and Cougar provided a much larger cut-out that allowed increased air flow. It appears air conditioned and some high-performance Mustangs used a battery heat shield in this time frame.
This D4DB-10A682-AA shield is commonly faked as a real D0OB shield. It is almost identical in measurements except about ½-inch shorter in height. Often, the D4DB molded prefix is ground off as people try to sell this version as an original D0OB shield.
The only heat shield reproduction to date is the second version, molded in a black plastic with the correct C7OB-10A682-B and C7ZB-10A682-B engineering numbers but without the FoMoCo logos.
A quick way to identify the reproduction when installed in a car is by the mold injection point. The original has the injection point in the center (as seen here).
The mold injection point for the reproduction heat shield is off center.