I believe the Z82 option is fairly rare, and have done some research on it...
I believe the option was more of a marketing option than a performance or capability option.
The Z82 trailering special package, which was introduced just after the start of the '73 model year, included the "Trailering Special" nameplate, power steering, and a heavy duty battery.
The package also usually required (but did not include) the purchase of other options, including heavy duty cooling (i.e. a larger radiator), and possibly engine and transmission oil coolers.
In earlier years, the transmission oil cooler and the trailer hitch were available ONLY as dealer accessories. From the 1973 to 1981 model years, the trailering special option was available on essentially all C/K10/20/30 pickups, Blazers, and Suburbans with V8 engines and automatic or 4-speed manual transmissions.
I believe that the Z82 package was not at all special in terms of content.
Virtually anything included or required in/by the purchase of the package was available separately, except the actual nameplate itself. In fact, throughout much of the 1973 to 1979 GM "inside" dealer literature, the Z82 package was referred to as the "Trailering Special Nameplate" option.
As I understand it, 454-optioned trucks already came bundled with power steering, heavy duty battery, cooling, etc, the Z82 option only added the obligatory nameplate.
I believe that the Z82 option was actually listed as a "no cost" option, and added a nominal weight of "0 lbs" to the curb weight of the vehicle!
The 13,000 lb plate on this Burb suggests, a 454/3.73 axle powertrain, I will confirm axle ratio when I am under there performing the rear gear oil change.
