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.
The HZ GTS was ranked by many as Australia's premier performance car, a position that was consolidated in May 1978 when the 5.0 litre V8 became standard.
DATE OF INTRODUCTION
8WQ69 Monaro GTS Four Door Sedan
PRICES AT TIME OF INTRODUCTION
4.2 litre four speed manual - $8482
5.0 litre V8 - $237
Limited slip diff - $93
Power steering - $253
TOTAL NUMBER BUILT
Monaro GTS Four Door Sedan - 154,155
4.2 litre L32 (253 ci HC)
Bore and stroke 3.625 inches (88.8 mm) x 3.062 inches (75.0 mm)
OHV with hydraulic lifters, single camshaft
Twin barrel Stromberg carburettor
Power output (DIN) 130 kW) at 4800 rpm
Torque (DIN) 325 Nm at 3000 rpm
Compression ratio 9.4:1
5.0 litre L31 (308 ci)
Bore and stroke 4.0 inches (101.6 mm) x 3.062 inches (75.0 mm)
OHV with hydraulic lifters, single camshaft
Twin barrel Stromberg carburettor
Power output (DIN) 186 kW at 5000 rpm
Torque (DIN) 434 Nm at 3400 rpm
Compression ratio 9.7:1
M20 3.05:1 first 4 speed
M21 2.54:1 first 4 speed
M41 Turbo-hydramatic 400
REAR AXLE RATIOS
LSD was available in all as a option also.
Four speed manual standard with 4.2, not available with 5.0.
Four speed high performance manual standard with 5.0 and optional with 4.2.
Hydra-Matic optional with both 4.2 and 5.0
Recirculating ball. (Power assisted from May 1978)
Front Power assisted discs
Rear Power assisted discs
Total length (inches/mm):190.3 inches (4834 mm)
Total width (inches/mm):73.9 inches (1877 mm)
Total height (inches/mm) at kerb weight:53.7 inches (1364 mm)
Wheelbase (inches/mm):111.0 inches (2719.5 mm)
Front track (inches/mm):59.8 inches (1518 mm)
Rear track (inches/mm):60.5 inches (1537 mm)
1475 kg (3253 lbs)
12.1 m (39.7 ft)
FUEL TANK CAPACITY
75 litres (16.6 imp. gallons)
V8s - Top left of block.
Located right side front of frame.
The first four digits are the model number
8Q69 - Monaro GTS Sedan
The next letter is the engine identification
R - QR 253 (high compression 4.2 litre)
T - QT 308 (high compression 5.0 litre)
The next letter is the model year
G - 1977
H - 1978
J - 1979
The next two digits is the assembly plant code
H1-H4 - Brisbane
H5-H9 - Sydney
J1-J9 - Dandenong
L1-L5 - Adelaide
The next five numbers is the vehicle serial number which represents the sequence in which the vehicle was built at the particular plant.
The final letter is the series code Z for HZ
OTHER IDENTIFICATION MARKS
Squares for grille with GTS badge in centre. Dual headlights in black surround with parklights/indicators on side. Black rubber bumper strips. Front air dam and rear boot spoiler. Three slot vent under GTS badge in front guards. GTS and engine size badge on rear panel.
The HZ GTS was the first GTS/Monaro to have the twin headlight front.
Displayed the new updated grille which used the new Holden lion emblem.
Turn signal/indicator frames no longer had the horizontal bars.
Front fenders displayed the newly designed GTS badge. Located in line with the sports vents and above the body style line.
Deck lid also displayed the new GTS badge. Located above the lock in the centre of the deck lid.
Grille also displayed the badge. Located in the lower left section of the grille.
Deck lid displayed the RTS badge. Located on the lower left corner.
Deck lid displayed the engine designation. Located on the lower right corner.
For Quartz Halogen headlamps, Inner two where driving lights.
Instrument panel displayed the RTS badge. Located under the left side face level air outlet.
Instrument faces where all newly designed. Indicator marks where now displayed on the outside of the numerals. Indicator needles coloured yellow. Dash facia coloured black.
Front and rear windscreen reveal mouldings newly styled black and chrome finish.
Exhaust gas emission control was improved.
Engine coolant recovery system fitted to vehicles with factory air conditioning.
Radial Tuned Suspension. (RTS)
Four wheel power disc brakes.
Early production fitted with the 4.2 litre engine as standard equipment with the 5.0 litre as an option. From mid 1978 the 5.0 litre engine was standard and made the only engine avaiable. With the change the engine sizing badge on the deck lid was removed.
Steering wheel horn cap featured the new designed Holden lion emblem.
Front air dam and rear spoiler where standard. But could be deleted on order.
Rear tail light and turn signal assembly rims painted to body colour.
Sports Wheels (GTS rims) where standard. Where also colour coded to match body colour. With Wire wheels 14" x 6" 72 spoke and Polycast 14" x 7" rims available as options.
New unique colours available for the first time. Along with two tone combinations.
Optional two tone painted sports pinstripes. Originally available on factory delivered vehicles, later becoming dealer installed from early 1978.
Power steering standard with the introduction of the 5.0 litre as the standard engine.
Headlining material was made from a fine sandpaper texture material.
Optional cloth trim called "Tartan Plaid Cloth". Cloth trim interiors also featured a fold down centre armreast in the rear seat. A first for a Monaro/GTS.
Towards the end of the GTS production many items previously available as custom features on previous models where now included as standard equipment.
Aprox November 1978 the trim was changed over to the newer style Commodore style texture as the old stocks became deleted.
Trim colours where Black, Chamois, Buckskin and Tan. With the change to Commodore materials came the new colours Light Grey and Light Blue. Chamois and Tan where removed with the Commodore material introduction.
Late production 5.0 litre engines may have featured the revised prefix - ZT
The HZ GTS model discontinued before the end of the HZ production.
HZ GTS OPTIONS
RPO No. Description
AO1 Tinted Glass - All Windows (incl. AO2)
AO2 Tinted/Laminated Windshield
A22 Laminated Winshield
A31 Power Windows
A47 Rear Sear Lap and Shoulder Belts with Retractor
A8K Vinyl Roof Cover - Sierra
A9N Delete Air Dam and Rear Spoiler
B84 Exterior Ornamentation
CB1 Vinyl Roof Cover - Buckskin
CB3 Vinyl Roof Cover - Chamois
C27 Vinyl Roof Cover - Black
C60 Air Conditioning (incl. AO1, K96, UA1)
D85 Two Tone Paint Sports Striping
D99 Two Tone Paint
GU4 3.08:1 Rear Axle
GV4 3.36:1 Rear Axle
GV7 3.55:1 Rear Axle
G66 Superlift Shock Absorbers
G70 2.60:1 Rear Axle
G80 Limited Slip Differential
K96 55 Amp Alternator
L31 5.0 Litre Engine
M21 High Preformance 4 Speed Manual Gearbox
M40 Trimatic Gearbox
M41 Turbo-Trimatic Gearbox
M71 Wire Wheels
PE1 Polycast Wheels
UA1 Heavy Dusty Battery
UL5 Delete Radio
U57 Cassette Player
U75 Power Operated Rear Radio Aerial
U80 Rear Seat Speaker
VO1 Heavy dusty Radiator
V37 Chrome Bumpers
XS7 Anti-Theft Spring
XS9 Vinyl and Nylon Cloth Trim
XW3 Vinyl Roof Cover - Tan
XW5 Outback Equipment Package (incl. H/D Supsension)
XY9 Neutral Headlining - Chamois
Vinyl roof not available on early production vehicles (pre mid 78).
When introduced it was rependant on exterior colour and interior trim combonation.
Towards the end of the GTS production new vinyl roof colours where avaiable. They where Dark Carmine, Light Blue, Light Grey and Medium Green.
RPO XS9 on early vehicles featured Tartan plaid cloth trim with a central colour stripe reflecting the exterior colour of the vehicle. Later vehicles featured slightly different design Tartan Plaid Cloth with no central colour stripe.
RPO XW5 included RPO F72 which on its own was not available on the GTS.
Mid 1978 update featured the following RPO's as standard equipment AO1, A47, L31, M21 and N40.