This manual covers the HQ and HZ series, iconic Australian vehicles produced between 1971-1974 for the HQ and 1977-1980 for the HZ. These models represent significant milestones in history, with the HQ introducing a completely new platform and a wide range of engine options, including the renowned Red and V8 engines. The HZ built upon this foundation, featuring refinements like Radial Tuned Suspension (RTS) and improved emissions controls. Available in various body styles including sedan, station wagon, coupe, ute, and panel van, these vehicles were engineered for the diverse Australian landscape and continue to be cherished by enthusiasts. This comprehensive workshop manual provides detailed guidance for the maintenance, diagnosis, and repair of your HQ or HZ. It covers all major systems, from engine mechanicals and fuel systems to transmissions, suspension, brakes, steering, and the electrical system. Included are step-by-step procedures for component removal and installation, disassembly and assembly of major components, routine maintenance schedules, and troubleshooting guides with diagnostic flowcharts. Technical specifications, torque values, and fluid requirements are also provided, making this an essential resource for owners, DIY mechanics, and professional technicians seeking to preserve the integrity and performance of these classic Australian vehicles.