Like the LE coupe, the HZ GTS 4-door did not wear a Monaro badge, but the brochure produced for it certainly did, and it was officially designated a 'Monaro GTS sedan'. Holden was unwilling to let the legend lapse - especially when this final incarnation would take it out on such a high note.
The HZ series was launched in October 1977, as behind the scenes Holden geared up for its most drastic model shift ever, the 1978 launch of the Commodore.

The HZ brought remarkable advances in ride and handling with the introduction of Radial Tuned Suspension, delivering a Holden that tamed local road conditions better than any before it and handled the twisty bits with European-style competence.

Radial Tuned Suspension (RTS) had its biggest impact on the GTS, which with a mesh grille, subtle body stripes and detailing on optioned-up versions, revived aspects of the HG Monaro GTS. A four-headlight nose, body colour front and rear spoilers and bumpers and sports wheels also helped to make it more of a stand-alone package in the Monaro tradition.

The GTS came standard as a 4.2 V8, but you could add the 5.0 litre, power steering, plaid cloth seats, limited slip diff, electric windows and air-conditioning. Rear disc brakes were standard, seven inch polycast wheels or spoked wire wheels were optional.