The HX Holden offered subtle refinements over the HJ with minor styling updates, improved suspension, and refined comfort features. By 1977, Holden released the HZ Holden, the final iteration of the traditional Holden body before the VB Commodore.
The HZ Holden featured cosmetic updates, mechanical improvements, and better refinement, making it the most polished of the classic Holden full-size sedans, wagons, utilities, and performance models.
Design and Styling Comparison
Exterior Design
HX Holden:
- Mid-1970s body with subtle styling changes from HJ
- Sedan, wagon, panel van, and utility variants
- Chrome trim modest, Deluxe, Special, Monaro, and GTS trims highlighted
HZ Holden:
- Minor cosmetic updates over HX, including revised grille, bumpers, and tail lights
- Subtle changes to panel detailing and trim
- Sedan, wagon, panel van, and utility variants continued
- Deluxe, Special, Monaro, and GTS trims slightly refreshed
- More modern and clean appearance, retaining muscular stance
The HZ looked very similar to the HX but had a more polished, finished look with subtle modern touches.
Interior Design
HX Holden:
- Functional dashboard with clear instruments
- Comfortable bench seating for six
- Interior trim improved in Deluxe, Special, and Monaro
HZ Holden:
- Updated dashboard layout for better ergonomics and visibility
- Seats slightly more supportive and comfortable
- Interior finishes refined, especially in higher trims
- Cabin more comfortable and user-friendly
The HZ interior offered incremental improvements, making it the most comfortable of the mid-1970s Holden models.
Platform and Engineering Changes
Chassis and Suspension:
- HX: Fully boxed perimeter frame, independent front suspension, leaf-spring rear
- HZ: Minor suspension tweaks for smoother ride and better handling
- Steering slightly more precise, reduced body roll
Brakes and Safety:
- Drum brakes standard, optional disc brakes front
- Safety improvements included better seatbelt mounting
- Ride quality slightly smoother than HX
The HZ provided the most refined driving experience of this Holden generation.
Engine and Drivetrain Comparison
HX Holden Engines:
- “Red” six-cylinder engines: 173, 186 cu in
- V8 engines: 253, 308
- Rear-wheel drive, three-speed manual or optional four-speed/floor shift
HZ Holden Engines:
- Same engine range with minor tuning for smoother performance
- V8 engines refined for reliability and drivability
- Gearbox and clutch improved for smoother shifts
- Rear-wheel drive retained
- Optional floor-mounted four-speed manual in Monaro and GTS variants
Performance Comparison:
- HX: Strong, reliable engines, V8s offered sporty performance
- HZ: Slightly smoother and more refined, minor performance gains
- Both models offered excellent driving dynamics; HZ felt more polished
Model Range Comparison
HX Holden:
- 2-door and 4-door sedans, wagon, panel van, utility
- Deluxe, Special, Monaro, and GTS variants
HZ Holden:
- 2-door and 4-door sedans, wagon, panel van, utility
- Deluxe, Special, Monaro, and GTS trims refined
- Minor mechanical improvements improved comfort and drivability
The HZ maintained the versatility of the HX while offering a more refined driving experience.
Technology and Features
HX:
- Functional dashboard, optional heater and radio
- Focused on practicality and V8 performance
HZ:
- Updated dashboard with improved ergonomics and instrument clarity
- Optional heater, radio, upgraded interior trim
- Seats more supportive, cabin more comfortable
- Minor mechanical upgrades for smoother operation
- Radial Tuned Suspension
The HZ offered the most refined comfort and convenience features of the mid-1970s Holden models.
Driving Experience
HX Holden:
- Solid and reliable ride
- Powerful V8 engines for Monaro and GTS
- Comfortable for family and performance driving
HZ Holden:
- Slightly smoother suspension and more precise steering
- Refined ride quality and cabin comfort
- Powerful V8 engines retained with improved drivability
- Cabin quieter and more comfortable
The HZ delivered the most polished driving experience of this generation while retaining strong performance.
Reliability and Common Problems
HX:
- Reliable engines and mechanics
- Minor wear in suspension or trim
- Easy to maintain
HZ:
- Similar reliability with minor mechanical refinements
- Improved suspension and interior durability
- Slightly smoother operation over HX
Both models are dependable, with HZ offering the final refinements of this classic Holden era.
Ownership Costs Today
Purchase Price:
- HX: Collectible mid-1970s Holden
- HZ: Slightly more desirable due to refinement, comfort, and Monaro/GTS popularity
Parts Availability:
- Limited for both; HZ parts slightly easier to source due to later production
Running Costs:
- Both economical; HZ offered smoother operation and slightly improved comfort
- V8 models higher maintenance but deliver strong performance
Collector and Enthusiast Value
HX Holden:
- Appreciated for mid-1970s styling and Monaro V8 performance
- Transitional classic into late-1970s Holden era
HZ Holden:
- Highly collectible late mid-1970s Holden
- Refined styling, comfort, and V8 Monaro/GTS options make it highly desirable
- Deluxe, Special, and Monaro trims sought-after by enthusiasts
Choose HX if:
- You want a reliable mid-1970s Holden
- You value historical significance and classic styling
Choose HZ if:
- You want the most refined mid-1970s Holden
- You value improved comfort, minor mechanical upgrades, and collectible Monaro/GTS variants
Verdict – Which Is Better? The HX Holden offered solid mid-1970s styling, comfort, and V8 performance. The HZ Holden was the final evolution of this generation, featuring refined styling, improved suspension, interior upgrades, and polished driving dynamics. For collectors, HX is valued for its transitional appeal, while HZ is prized for refinement, comfort, and collectible Monaro/GTS models