TRIM is not a typo. Before TRAM (see http://tailspintopics.blogspot.com/2015/09/grumman-6a-vs-6e-intruder.html), there was TRIM (Trails, Roads, Interdiction Multisensor). It included a large belly-mounted pod that contained a Low-Light-Level Television (LLLTV) camera and a Forward-Looking Infrared (FLIR) camera. The LLLTV amplified images to make them more visible and the FLIR detected objects that were hotter than their surroundings.
Twelve A-6As, BuNos 155647, 648, 653, 660, 663, 667, 670, 674, 676, 681, 684, and 688, were modified to be A-6Cs. The installation of the pod required the addition of hard points on the bottom of the fuselage as well as cockpit and other minor hardware changes. They were all delivered in the first half of 1970.
Mick Roth recently provided me with additional documentation on the pod that answered some questions I had. This illustration is a work in progress.
The turret was rotated aft to protect the clear panels when the LLLTV and FLIR were not in use.
The windows were flat and not symmetric, with the narrower FLIR camera mounted in the right side of the turret looking through germanium composition glass and the LLLTV camera in the left side looking through quartz composition glass.
The production pod had air outlets on the side of the turret section instead of an inlet, the bottom of the turret opening had an extended lip, and the afterbody was extended downward to the bottom of the fins except for the last foot or so.
Although the A-6C SAC shows the inboard wing fences inboard of the inboard pylon like the A-6E, they were actually outboard of the inboard pylon like the A-6A.