Triumph Stag Originality

1. What originality means on a Stag

Because the Stag changed so little mechanically, originality here is mostly about the details: the wheels, the tail panel, the instruments, the badging and the trim. The 3-litre V8, the body shell and the fixed T-bar and roll hoop that define the car's silhouette were constant throughout. That makes the Stag refreshingly approachable to understand, but it also means the small details are where correctness is won or lost.

Two honest points to set the tone. First, there is no real price premium for a later car: a superb Mk1 is worth more than a tired Mk2, so buy on condition and originality, not on the mark. Second, originality is a spectrum, not a test you pass or fail. A concours car should be correct in every detail, but most Stags are enjoyed as drivers, and sensible improvements, a better radiator and an electric fan above all, are widely accepted and do not make a car any less of a Stag. This guide sets out what is original so you can make an informed choice, not so you can feel bad about a well-judged upgrade.

The final authorities are the car's commission plate and a Heritage Certificate from the British Motor Industry Heritage Trust, which records how the car was actually built. The standard printed reference is the book The Original Triumph Stag: The Restorer's Guide, and the Stag Owners Club keeps the definitive record of the changes.

2. Dating your car: the commission number

Every Stag carries a commission number (prefixed LD, for example LD20001) on its commission plate, and the number places the car in the production run. These are the Stag Owners Club's ranges.

For reading the commission plate and the engine and gearbox numbers in full, and for checking a car is genuine, see the Identification guide.

3. The Mk1 in detail (1970 to 1973)

The original car. Its hallmarks:

• Wheels. Steel wheels with Rostyle trims.
• Body. Fully colour-coded, with no coachlines and a body-colour tail panel.
• Instruments. The earlier dashboard, with the speedometer and rev-counter needles hanging downward at rest, a warning-lamp cluster, a map-reading light in the glovebox lid, and interior lights on the B-posts.
• Hood. The Mk1 soft top has rear quarter windows, and a single spring clip to hold it when stowed.
• Steering wheel. Larger than the later car's.
• Badging. A larger Triumph plinth at the rear, as the number-plate lights were not yet in the boot lid.

4. The Mk2 in detail (1973 to 1977)

Introduced for the 1973 model year (from LD20001), the Mk2 arrived in stages.

• From 1973. A matt black rear tail panel and sills, coachlines, the well-known GKN alloy wheels, clearer revised instruments, new seats, a revised hood without rear quarter windows, a slightly smaller steering wheel, revised badging with a smaller Triumph plinth (the number-plate lights moved to the boot lid), and a factory hard top as standard.
• From October 1975 (around LD40001). The black tail panel was dropped for a body-colour one, alloy or stainless sill covers were added, and tinted glass was fitted.
• From October 1976. The Borg-Warner BW65 automatic replaced the earlier BW35, along with a smaller radiator and an altered steering ratio.
• An originality tell. On original GKN alloy wheels the tyre valve sits in front of a spoke. Aftermarket copies often place the valve between the spokes.

5. The Mk1.5

You will hear the term Mk1.5, though it was never a factory designation and owners define it slightly differently. It usually means the 1973 model-year cars in the LD20001 series, which combine a Mk1-style body with Mk2 fittings such as the seats, hood, instruments and badging. A distinguishing detail often quoted is that these cars do not have hazard lights. Treat the term as useful shorthand rather than an official mark.

6. Mechanical originality

Mechanically the Stag barely changed. A correct car has the 2997cc Triumph SOHC V8 of around 145 bhp, breathing through twin Zenith-Stromberg 175 CD carburettors, with either a four-speed manual gearbox (overdrive optional) or a Borg-Warner automatic, the BW35 giving way to the BW65 for 1976 to 1977. All-round independent suspension, rack-and-pinion power steering and front disc brakes were fitted throughout, as was the fixed T-bar and roll hoop.

The commonest departure from originality is under the bonnet: many Stags have been fitted with the Rover V8 or other engines over the years, usually to escape the original engine's reputation. A converted car is not original and its commission and engine numbers will not match, but a good conversion is a perfectly valid ownership choice. If matching numbers matter to you, confirm them against the plate and the Heritage Certificate, as covered in the Identification guide.

7. Colours and trim

Do not judge a Stag's colour by its current paint. The correct factory colour and trim are recorded on the commission plate and confirmed by the Heritage Certificate, and a Stag may well have been resprayed, sometimes in a colour it never originally wore. Triumph offered a range of period colours across the production run, and the Mk1 was fully colour-coded where the early Mk2 had its contrasting black tail panel. If originality matters to you, take the colour from the records, not from the bodywork.

8. The originality caveats

Two things make Stag originality less clear-cut than it first appears. Triumph used up old stock across the model changes, so a genuine early Mk2 can legitimately carry Mk1 parts such as a wiring loom or door latches, and the reverse happens too; a blended car may be exactly as it left the factory. And over fifty years many Mk1s have quietly acquired Mk2 wheels, coachlines and fittings, so what is on a car today is not proof of what it was born with. Judge originality against the build records, not against assumptions or against what happens to be fitted now.

Frequently asked