The Guy Invincible II range consisted of heavy duty versions of the Warrior II series. There were capable of transporting heavier loads, while still retaining the same high degree of driver comfort, and ease of operation.

The cab assembly was in two sections which split at a flat waist line. The top was easily removable for maintenance etc. Fittings included a full-width visor, twin air operated windscreen washers, electrically operated wipers, twin interior lights, twin seats, fully adjustable driving seat, and twin telescopic mirrors. Optional extras included a large fresh air heating and ventilating unit, external double skin roof, roof ventilator, and an interior sun visor for the passenger.

There were two options for engines which could be fitted as standard. The first was the smaller 9.8 litre six-cylinder 125bhp engine and the second was the larger 11.1 litre six-cylinder 150bhp engine. Alternative engines of up to 220bhp were also available if required. A six-speed constant mesh gearbox with overdrive on top gear was fitted. Provision was made for a power take-off. Alternative 6, 10, or 12-speed gearboxes were available. A large diameter hydraulically operated clutch was fitted.

A Bendix-Westinghouse dual air brake system was fitted. This incorporated low pressure warning buzzer. Exceptionally long 4" wide semi-elliptic leaf-springs were fitted. They were 50 inches long at the front and 60 inches long at the rear. The chassis was made of carbon manganese steel pressings which were 12" deep x 3" wide.

24 volt lighting and starting equipment insulated return with compensated voltage control was fitted. Batteries supplied in four 6 volt units, capacity being 102 amp hours. A cylindrical welded steel tank with a capacity of 50 gallons. Larger capacities were available on request.