In 1958, all Chevrolet models were updated. It definitely stood they out from the previous units. Among the changes were quad-headlights, a new and much wider grille with integral parking lights, new dashboard and interior, and new series designations.
The high-duty series 8000 and 10000 received the name Spartan. Spartans had GVW ratings of up to 25,000 pounds for single rear axles. The standard for the heavy duty range was 283 cubic inch Super Taskmaster V8 or Workmaster 348 cubic inch V-8 engine of 230 horsepower. When combined with the 5-speed Spicer transmission, a new 3-speed power divider gave a total of 15 forward speeds. Powermatic 6-speed automatic transmission could be ordered for extra cost.
New to Chevrolet’s heavy duty range of this year were factory made tandems chassis. The 8000 series (Series 80 somewhere) tandem featured twin 15,000-pound capacity rear axles and a 7000-pound front axle, to give a GVW of 28,000 or, for tractor use, a GCW of 45,000 pounds.
The largest chassis/cab unit was the Series 10000 (Series 100 somewhere) with tandem rear axles and GVW ratings of up to 36,000 pounds and GCW ratings of 50,000 pounds. These chassis were available in 156.5, 174.5 and 192.5-inch wheelbases.