Holden HK-HG Monaro, Full Specifications

Key Specifications

Spec	HK (1968-1969)	HT (1969-1970)	HG (1970-1971)
Production Years	1968-1969	1969-1970	1970-1971
Manufacturer	General Motors-Holden’s	General Motors-Holden’s	General Motors-Holden’s
Assembly	Elizabeth, South Australia / Pagewood, Sydney / Dandenong, Melbourne	Same	Same
Body Style (Monaro)	2-door pillarless coupe	2-door pillarless coupe	2-door pillarless coupe
Body Style (Sedan)	4-door sedan	4-door sedan	4-door sedan
Layout	Front engine, rear-wheel drive	Front engine, rear-wheel drive	Front engine, rear-wheel drive
Construction	Steel unibody (monocoque)	Steel unibody (monocoque)	Steel unibody (monocoque)
Wheelbase	2,819 mm (111 in)	2,819 mm (111 in)	2,819 mm (111 in)
Overall Length	4,724 mm (186 in)	4,724 mm (186 in)	4,737 mm (186.5 in)
Overall Width	1,854 mm (73 in)	1,854 mm (73 in)	1,854 mm (73 in)
Overall Height	1,384 mm (54.5 in) coupe	1,384 mm (54.5 in) coupe	1,384 mm (54.5 in) coupe
Kerb Weight (six)	1,250 kg (2,756 lb)	1,260 kg (2,778 lb)	1,260 kg (2,778 lb)
Kerb Weight (V8)	1,380-1,470 kg (3,042-3,241 lb)	1,390-1,480 kg (3,064-3,263 lb)	1,390-1,480 kg (3,064-3,263 lb)
Fuel Tank Capacity	68 L (15 imp gal)	68 L (15 imp gal)	68 L (15 imp gal)
Boot Capacity	~380 L (coupe)	~380 L (coupe)	~380 L (coupe)
Seating Capacity	5 (GTS bucket seats) / 6 (bench seats)	5 / 6	5 / 6

Engine Specifications

186ci Holden Six (3,048 cc)

Spec	Value
Configuration	Inline 6, OHV, 12-valve
Displacement	3,048 cc (186 ci)
Bore x Stroke	92.1 mm x 76.2 mm
Compression Ratio	8.25:1
Power	115 bhp (86 kW) @ 4,400 rpm
Torque	231 Nm (170 lb-ft) @ 2,000 rpm
Fuel System	Stromberg single-barrel carburettor
Block Material	Cast iron
Head Material	Cast iron

253ci Holden V8 (4,146 cc)

Spec	Value
Configuration	V8, OHV, 16-valve
Displacement	4,146 cc (253 ci)
Bore x Stroke	92.1 mm x 77.8 mm
Compression Ratio	9.0:1
Power	185 bhp (138 kW) @ 4,800 rpm
Torque	325 Nm (240 lb-ft) @ 2,800 rpm
Fuel System	Rochester 2-barrel carburettor
Block Material	Cast iron
Head Material	Cast iron

307ci Chevrolet V8 (5,031 cc), HK Only

Spec	Value
Configuration	V8, OHV, 16-valve
Displacement	5,031 cc (307 ci)
Bore x Stroke	98.6 mm x 82.6 mm
Compression Ratio	9.0:1
Power	200 bhp (149 kW) @ 4,600 rpm
Torque	380 Nm (280 lb-ft) @ 2,400 rpm
Fuel System	Rochester 2-barrel carburettor
Block Material	Cast iron
Head Material	Cast iron

327ci Chevrolet V8 (5,359 cc)

Spec	Value
Configuration	V8, OHV, 16-valve
Displacement	5,359 cc (327 ci)
Bore x Stroke	101.6 mm x 82.6 mm
Compression Ratio	10.0:1
Power	250 bhp (186 kW) @ 4,800 rpm
Torque	420 Nm (310 lb-ft) @ 3,200 rpm
Fuel System	Rochester Quadrajet 4-barrel carburettor
Block Material	Cast iron
Head Material	Cast iron

350ci Chevrolet V8 (5,733 cc), HT and HG

Spec	Value
Configuration	V8, OHV, 16-valve
Displacement	5,733 cc (350 ci)
Bore x Stroke	101.6 mm x 88.4 mm
Compression Ratio	10.25:1
Power	300 bhp (224 kW) @ 4,800 rpm
Torque	475 Nm (350 lb-ft) @ 3,200 rpm
Fuel System	Rochester Quadrajet 4-barrel carburettor
Block Material	Cast iron
Head Material	Cast iron

Transmission Options

Transmission	Type	Gears	Applications
Saginaw	Manual	3-speed	Six-cylinder base models
Saginaw	Manual	4-speed	253 V8, some six-cylinder
Muncie M20 (wide ratio)	Manual	4-speed	327 V8, 350 V8
Muncie M21 (close ratio)	Manual	4-speed	GTS 327, GTS 350
Powerglide	Automatic	2-speed	Six-cylinder, some 253 V8
Turbo-Hydramatic 350	Automatic	3-speed	327, 350, some 253 V8

Muncie M21 Close-Ratio Gear Ratios

Gear	Ratio
1st	2.20:1
2nd	1.64:1
3rd	1.28:1
4th	1.00:1
Reverse	2.27:1

Turbo-Hydramatic 350 Gear Ratios

Gear	Ratio
1st	2.52:1
2nd	1.52:1
3rd	1.00:1
Reverse	1.93:1

Differential

Model/Engine	Ratio	LSD
186ci six (manual)	3.55:1	No
186ci six (auto)	3.36:1	No
253ci V8 (manual)	3.36:1	No
253ci V8 (auto)	3.08:1	No
327ci V8 (manual)	3.36:1	Optional
327ci V8 (auto)	3.08:1	Optional
GTS 327 (manual)	3.55:1	Yes
350ci V8 / GTS 350 (manual)	3.55:1	Yes
350ci V8 / GTS 350 (auto)	3.36:1	Yes

Suspension

Front

Spec	Value
Type	Independent, double wishbone
Springs	Coil
Dampers	Telescopic hydraulic
Anti-roll Bar	Standard (V8 and GTS), optional (six)
Steering Type	Recirculating ball
Power Steering	Standard (GTS), optional (others)
Turning Circle	11.9 m (39 ft)

Rear

Spec	Value
Type	Live axle
Springs	Coil
Dampers	Telescopic hydraulic
Location	Trailing arms with Panhard rod
Anti-roll Bar	Optional (GTS, some V8 models)

Brakes

Spec	Standard	GTS
Front	Drum, 254 mm (10 in)	Disc, 273 mm (10.75 in), PBR calipers
Rear	Drum, 254 mm (10 in)	Drum, 254 mm (10 in)
Power Assistance	Optional	Standard (vacuum booster)
Handbrake	Mechanical, rear drums	Mechanical, rear drums

Electrical

Spec	Value
System Voltage	12V negative earth
Charging	Alternator (most models), generator (early HK six-cylinder)
Battery	12V, 50 Ah (six), 60 Ah (V8)
Starter	Pre-engaged
Headlamps	Twin sealed beam, 5.75 in

Model Variants, Monaro Coupe

HK Monaro (1968-1969)

Variant	Engine Options	Key Features
Monaro	186ci six, 253ci V8	Base coupe, pillarless body, bench or bucket seats
Monaro GTS	327ci V8	Full GTS package, bucket seats, full instruments, body stripes, rally wheels, front disc brakes, HD suspension

HT Monaro (1969-1970)

Variant	Engine Options	Key Features
Monaro	186ci six, 253ci V8	Base coupe
Monaro GTS	253ci V8, 350ci V8	GTS package, 350 standard on GTS 350

HG Monaro (1970-1971)

Variant	Engine Options	Key Features
Monaro	186ci six, 253ci V8	Base coupe, revised grille and tail-lights
Monaro GTS	253ci V8, 350ci V8	GTS package as HT with cosmetic updates

Performance (approximate, period road tests)

Model	0-100 km/h	Quarter Mile	Top Speed
HK Monaro 186 six (manual)	~15 s	~19 s	150 km/h
HK Monaro 253 V8 (manual)	~11 s	~17.5 s	175 km/h
HK Monaro GTS 327 (manual)	~7.5 s	~15.2 s	200 km/h
HT/HG Monaro GTS 350 (manual)	~6.8 s	~14.5 s	215 km/h
HT/HG Monaro GTS 350 (auto)	~7.5 s	~15.0 s	210 km/h

Fuel Economy (approximate, mixed driving)

Model	L/100 km
186ci six (manual)	12-15
253ci V8 (manual)	14-17
327ci V8 (manual)	16-20
350ci V8 (manual)	18-24
350ci V8 (auto)	19-25

Service Intervals

Service Item	Interval
Engine oil and filter	5,000 km or 6 months
Spark plugs	15,000 km
Points and condenser	8,000-10,000 km
Distributor cap and rotor	20,000 km
Automatic transmission fluid	40,000 km
Chassis lubrication (grease nipples)	5,000 km
Coolant	40,000 km or 2 years
Brake fluid	24 months
Front suspension check	20,000 km

Engine Oil Specifications

Engine	Recommended Grade	Capacity (with filter)
186ci Holden six	15W-40 mineral / 20W-50 mineral	4.3 L
253ci Holden V8	15W-40 mineral / 20W-50 mineral	4.7 L
307ci Chevy V8	10W-40 semi-synthetic / 15W-40 mineral	4.7 L
327ci Chevy V8	10W-40 semi-synthetic / 15W-40 mineral	4.7 L
350ci Chevy V8	10W-40 semi-synthetic / 15W-40 mineral	4.7 L

Tyre Specifications

Variant	Original Size	Common Modern Replacement
Standard (six-cylinder)	7.00-14 crossply	195/75R14 radial
V8 models	7.35-14 crossply	205/75R14 radial
GTS 327	E70-14 (185/70R14)	205/70R14 radial
GTS 350	F70-14 (205/70R14)	215/70R14 radial
Rim Size (standard)	14 x 5J	14 x 5J or 14 x 6J
Rim Size (GTS)	14 x 6J rally wheels	14 x 6J or 14 x 7J

Differential Specifications

Spec	Value
Type	Salisbury (V8 and GTS), Banjo (six-cylinder)
LSD Type (GTS)	Eaton Posi-traction
Axle Type	Semi-floating

Production Numbers

Model	Total Production
HK, All variants (sedan + coupe)	~127,000
HK Monaro coupe (all engines)	~5,400
HK Monaro GTS 327	~1,600
HT, All variants	~107,000
HT Monaro coupe (all engines)	~4,200
HT Monaro GTS 350	~1,250
HG, All variants	~100,000
HG Monaro coupe (all engines)	~3,300
HG Monaro GTS 350	~800
Total Monaro coupes	~12,912
Total GTS models (327 + 350)	~3,650

GTS Standard Equipment (HT/HG GTS 350)

Feature	Detail
Engine	350ci Chevrolet V8, 300 bhp
Carburettor	Rochester Quadrajet 4-barrel
Transmission	4-speed Muncie M21 manual or TH350 automatic
Differential	3.55:1, Eaton Posi-traction LSD
Front Brakes	Ventilated disc, PBR calipers
Rear Brakes	Drum, 254 mm
Power Steering	Standard
Brake Booster	Standard
Suspension	Heavy-duty springs, HD dampers, front and rear anti-roll bars
Seats	Bucket seats, vinyl
Instrumentation	Full cluster, speedo, tacho, oil pressure, water temp, ammeter, fuel
Wheels	14 x 6J rally wheels
Exterior	Body stripes, GTS badges, dual exhaust