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GT6  Model MKIII  Specifications

As best I have been able to determine, the following information
is the general specifications for the MKIII model Triumph GT6.
This table primarily covers the US market accept where noted.
I have made all reasonable attempts to verify all information
contained here. It is by no means, that I claim these are
the true and only versions of these numbers you'll find.




Build Quantities Total number: 13,042.
US Market: Oct 1970  to Dec 1973.
Chassis numbers: FM10001U to FM95001UC
US Market:
Chassis numbers see 'serial numbers'*

Capacities US market other markets Note:
   Late models have
an 'expansion zone'
within the tank which
limits  the maximum
amount  of fuel you
can put in the tank
to 8.7 US gals.
Fuel 9.9 gallons 37.6 liters
Engine oil with filter change 4.75 quarts 4.5 liters
Engine oil without filter change 4.25 quarts 4.0 liters
Gearbox .9 quarts .85 liters
Gearbox with overdrive .1.4 quarts 1.35 litters
Rear end .6 quarts .57 liters
Cooling System 4.75 quarts  4.5 liters

Engine Specs. US market other markets


Number of cylinders 6 in line 6 in line
Bore of cylinders 2.94 in  (74.7 mm) 74.7 mm
Stroke of crankshaft 2.99 in  (76mm) 76 mm
Capacity 122 cubic in (1988 cc) 1988 cc
Compression ratio 9.25:1 (1976 - 9.0:1) 9.25:1
Maximum power 98 b.h.p. SAE net
@ 5300 rpm
98 b.h.p. SAE net
@ 5300 rpm
Maximum torque 108 lb/ft
@ 3000 rpm
108 lb/ft
@ 3000 rpm
firing order 1-5-3-6-2-4

Lubrication  Note:
normal pressure
75 psi+/- 5 cold
dropping to 25 psi
warm is not
Oil pump High capacity rotor type
Oil filter Full flow type, disposable cartridge
Oil warning light Extinguishes at 3 to
5 lb/in2 oil pressure

Cooling System 
Type 'No-loss' Water system
Circulation impeller type pump, Vee belt driven
Pressure 13lb/in2 (0.91kg/cm2)
Thermostat. Opens at 180° F (82° C) - 190° F (88° C) 

Fuel system
Tank (limited fill fuel tank) 9.9 gallons (fillable to 8.5) - US market 37.6 liters -other markets
Pump Mechanically operated diaphragm type
Carburetor Twin Stromberg 150 CDSE side draught
Air Cleaner U.S.A. models fitted with a temperature
controlled inlet air flow
Combined air cleaner
and silencer  with
replacement paper
Closed circuit breathing from rocker cover to
constant depression side of carburetors.
Emission control
U.S.A. models only, sealed tank filler cap. Vapor emissions from tank are
vented via a separator canister  to a carbon canister located in the engine
compartment.  Canister is purged by carburetor depression. An air pump
injects air into each exhaust port via a distribution manifold and an  E.G.R.
valve. A service indicator located in the engine  bay illuminates a warning
light on the fascia when the  E.G.R. valve is due for periodical maintenance.

Clutch  Note:
Make/type Borg and Beck, single dry plate,
diaphragm spring type
Release mechanism Hydraulically operated
Plate diameter 8 1/2" (215.9mm)
Facing material Borg and Beck 11046 H.K. Porter 11046



Synchromesh - On forward gears

Gear 1st 2nd 3rd 4th Rev. O/D 3rd O/D 4th
Ratio 2.65 1.78 1.25 1.00 3.10 1.1 0.81

Overdrive (Optional) 

Make/type Laycock J-Type
Operative on 3rd and 4th gears via
transmission interlock switch
Overall ratio 0.81:1

Rear Differential  



* gearing values depending on type and condition of tires


** speed values depending on type and condition of tires

Type - Hypoid bevel gears in rear axle
Ratio 3.89:1
with O/D
-without O/D
Effective Gearing *
gear 1st 2nd 3rd 4th O/D 3rd O/D 4th
Engine speeds
(rev/min) at road speed ** of
10 mph-U.S.A.
Non U.S.A.
4th gear
Road speed at 1,000 re/min engine speed in 4th gear - O/D engaged

Make/Type Alford & Alder, rack and pinion
Turning circle
Steering wheel diameter
Turns lock to lock

Brake System
Foot pedal Tandem master cylinder operating front and
rear brakes independently 
Hand brake Mechanical on rear wheels only
Type Caliper disc front, Drums rear
Disc diameter 9.7 in (246.38mm)
Disk Lining area
Disk Swept area

Wheels And Tires  Note:
Wheels 4 1/2 x 13 Steel disc type
Tires 155SR x 13 in radial ply
Tire pressures- front 21 lb/in2 (1.476 kg/cm2)
Try pressures- rear 26 lb/in2 (1.828 kg/cm2)

Chassis Data  
Wheelbase 83" (2110 mm)
Front track width
(2 up condition):
49" (1244 mm)
rear track width 49" (1244 mm)
Front wheel alignment
(2 up condition)
0 - 1/16" toe in (0 - 1.5875 mm)
rear wheel alignment
(2 up condition)
0 - 1/16"  toe in (0 - 1.5875 mm)
Ground clearance
(2up condition)
5" (127 mm)
Front Camber
(2 up condition) 
2° positive +1/2°
Rear Camber
(2 up condition)
3 1/4° negative + 1
Caster (2 up condition) 4 1/2° + 1/2°
King Pin inclination
(2 up condition)
6 3/4° + 3/4°

Electrical Equipment

   Only three
fuses protect
the entire car.
Electrical System 12 volt negative earth
Battery capacity 40 amp hour at 20 hour rate
Alternator type Lucas 16 ACR output 34 amps
Starter motor M.35 J inertia type

Overall Dimensions US market other markets
Height (unladen) to top of windscreen
Soft top hood erect
Hard top

Weights (approx) US market other markets
Dry (excluding extra equipment) 1976-80 804 kg,1761 lb (799 kg) 763 kg
Basic Kerb (including fluids and tools) 1976-80 829 kg, 1814 lb (823 kg) 792 kg
Kerb (fully running with all std equipment) 1976-80 876 kg, 1900 lb (862 kg) 841 kg
Maximum gross vehicle weight 1976-80 1061 kg, 2339 lb (1061 kg) 1036 kg
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All material copyright© Teglerizer 1996-2008

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