Commission & engine numbers
Identification
The commission plate on the scuttle/bulkhead is the most reliable way to identify a Stag. It carries the commission number, paint code and trim code. Use that number, not styling cues, to place a car in the production run.
The commission plate
The plate is riveted to the scuttle/bulkhead beneath the bonnet, on the passenger side. It is the car's factory identity card and should match the paperwork.
- Commission number
- The build-sequence number used to date the car and verify its place in the production run.
- Paint code
- The factory colour. Earlier cars use two/three-digit numeric codes; from March 1977 the system changed to three-letter codes.
- Trim code
- The interior trim specification. Cross-reference this with the Stag Owners Club records.
Always verify a car's exact specification from the commission plate and the Stag Owners Club register, not by eye alone.
Commission-number guide
The ranges below are drawn from the Stag Owners Club's records and are approximate at the boundaries. They are the same ranges used on the Mk1 vs Mk2 page.
| Commission range | Model year | Enthusiast designation |
|---|---|---|
| 1 – ~3,900 | 1970 pre-production & 1971 | Early / "Mk1" |
| 10,001 – 14,158 | 1972 model year | "Mk1" |
| 20,001 – 25,432 | 1973 model year | Early "Mk2" matt-black tail panel & sills |
| 30,001 – 36,714 | 1974 / 75 model year | "Mk2" |
| 40,001 – 45,722 | 1976 / 77 model year | Late "Mk2" body-colour tail panel, alloy sill covers |
Source: Stag Owners Club commission-number records. Boundary commission numbers are approximate.
The engine number, the check that matters most
On a Stag the engine number is arguably the most important number of all, not for dating the car, but because it tells you whether the car still has its original Triumph V8. The V8's unfair reputation led many owners to replace it over the years, commonly with a Rover V8 or another unit, so a Stag that keeps its original, matching-numbers Triumph V8 is worth appreciably more than a converted one, it is the first check a serious buyer makes.
- LF
- Stags for all markets except the USA.
- LE
- US Federal (emissions) Stags. Early Federal cars carried LD before LE was adopted around 1972.
- Any other prefix
- An engine number not beginning LF or LE, or a block visibly not the Triumph V8, is not the original-type engine.
How to read an engine number
A Stag engine number is prefix + serial + suffix, e.g. LF 11246 HE:
- Prefix, LF (non-US) or LE (US Federal). The LD prefix only appears on the earliest Federal cars.
- Serial, 11246 is the build sequence. It does not exactly match the commission number but is usually in the same numerical range.
- Suffix, HE means H = high compression and E = engine. The "E" distinguishes it from a commission number. Low-compression engines carry L; US cars may carry U for pollution equipment or C for California/catalyst.
As a rough guide the factory changed engine internals around LF/LE 20001, so a serial of 20001+ indicates a later "Mk2"-era engine.
Early cars
Stamped on a cast boss between the two rearmost spark plugs on the left-hand cylinder bank.
From October 1971
At the back of the cylinder block, between the distributor and the bellhousing.
The body number
A separate small plate on the front body crossmember, beside the left-hand bonnet hinge, carries the body number (it begins T 001 LD). It does not match the commission number, though usually close, and is of no practical use when ordering parts; its value is as an originality cross-check.
Transmission cross-checks: because the factory changed components at known commission points, a few milestones help confirm a car's period, the overdrive changed from the "A" type to the "J" type at commission LD21231 (LE20857 US), and the automatic gearbox changed from the Borg-Warner Type 35 to the Type 65 at LD41994. A gearbox or overdrive that doesn't match isn't necessarily wrong (these are commonly swapped), but it is a useful cross-check.
Factory colours
The Stag was unusual for Triumph in offering several metallics alongside its solid colours. The exact shade and code for a particular car should be taken from the commission plate, not from photographs or memory.
Solids
- Pimento Red
- British Racing Green
- Carmine Red
- Mimosa Yellow
- Java Green
- Topaz Orange
- Magenta
- Maple Brown
- Russet Brown
- White (Leyland / Pure White)
- French Blue
- Delft Blue
- Tahiti Blue
Metallics
- Astral Blue
- Tara Green
- Midas Gold
- and other BL metallics of the period
Paint-code change: in March 1977 Triumph switched from two/three-digit numeric paint codes to three-letter codes (the first letter denotes the colour group). Late cars may therefore carry letter codes on the commission plate rather than numbers.
Commission-number decoder
Enter a commission number to see which published production range it falls into. This is an indicative guide only, it is not a lookup of that individual car's factory record.
For the authoritative history of a specific car, contact the Stag Owners Club with the commission number, chassis number and any paperwork.
Matching numbers & the Heritage Certificate
“Matching numbers” on a Stag means the engine and body numbers on the car are those the factory recorded against its commission number. The definitive record is held by the British Motor Industry Heritage Trust (BMIHT) at Gaydon, which holds the original Triumph build records; a Heritage Certificate lists, for a given commission number, the engine number, body number, original colour and trim, and the build and dispatch dates. For a car so often modified and engine-swapped, it is the single best way to turn “it looks original” into documented originality, and the first document to ask for when buying.
For the original build details of a specific car, contact the Stag Owners Club or the British Motor Industry Heritage Trust with the commission number.
Step-by-step: checking a Stag's numbers before you buy
Work through these in order. Each step either confirms the last or tells you to stop and ask a question, do them in sequence and you will know, before any money changes hands, whether the car is what the advert says it is.
Read the commission plate first
Find the plate on the scuttle/bulkhead and write down the commission number, paint code and trim code exactly as stamped. Everything else is checked against this. A missing, loose, re-riveted or freshly painted plate is a reason to slow down, not a detail to overlook.
What to check
- The plate is present, flat and original-looking, with factory rivets rather than pop rivets or screws.
- Every character is legible; photograph it and transcribe the commission, paint and trim codes in full.
- Stamping is even in depth and spacing, re-stamped or hand-punched characters are irregular.
- The paint and trim codes agree with the colour and interior actually fitted, or the difference is explained.
Where it's explained: The commission plate · Colour and trim codes
Check the commission number against the production run
Use the decoder above to see which published range the number falls into, then ask whether the car in front of you fits that period. A number that places the car in one year while the seller describes another needs explaining.
What to check
- The number falls inside a published commission range, not outside every range.
- The range's period matches the year on the V5C and the year in the advert.
- Mk1 or Mk2 features on the car (grille, wheels, trim) suit the period the number indicates.
Where it's explained: Commission number ranges · Production & survival data · Mk1 vs Mk2
Find and read the engine number
It is stamped at the back of the cylinder block, between the distributor and the bellhousing, see the engine number section. Clean the area and read it yourself rather than accepting a number from the advert or the paperwork. A prefix that does not match the market the car was built for is the first sign the engine has been changed.
What to check
- You have read the stamp on the block yourself, with a torch and mirror, rather than copying the advert.
- The prefix suits the market: LF for home and general export, LE (early LD) for US Federal cars.
- Any suffix letter is recorded, it points to the emissions specification.
- The number is not ground, filled or over-stamped.
Where it's explained: The engine number · US Federal-spec cars
Confirm the engine is a Stag V8 at all
Many Stags have been re-engined, most often with a Rover V8. That is not automatically a fault, plenty are well done, but it ends any matching-numbers claim, and it should be reflected in the price. See the V8 engine guide for what the original unit looks like.
What to check
- The engine physically matches the Triumph V8 described in the engine guide, not a Rover or other substitute.
- If it is a conversion, ask what was changed with it: cooling, mountings, gearbox, wiring and V5C entry.
- The V5C engine number reflects whatever is actually in the car.
Where it's explained: The Triumph V8 · Rover V8 conversions
Check the body number
The small plate on the front body crossmember, beside the left-hand bonnet hinge, carries the body number. It will not be identical to the commission number, usually close, so treat it as a cross-check on originality rather than a second chassis number.
What to check
- The plate is present on the front body crossmember, beside the left-hand bonnet hinge.
- The number is in the same general sequence era as the commission number.
- The surrounding panel work looks original rather than replaced around a transplanted plate.
Where it's explained: The body number · Bodywork checks in the buying guide
Cross-check the transmission against known change points
The overdrive changed from the “A” to the “J” type at commission LD21231 (LE20857 US), and the automatic changed from the Borg-Warner Type 35 to the Type 65 at LD41994. Gearboxes are commonly swapped, so a mismatch is not proof of anything, but it is a question worth asking.
What to check
- Manual or automatic as described, and as recorded on the V5C.
- Overdrive type against the LD21231 (LE20857 US) change point.
- Automatic type against the LD41994 change from Borg-Warner 35 to 65.
- If a five-speed or other modern box is fitted, ask who did the work and whether it is documented.
Where it's explained: Manual vs automatic · Clutch & overdrive · ZF conversions
Compare everything with the paperwork in front of you
Check the commission and engine numbers against the V5C (or your country's equivalent), old MOTs, invoices and any previous advertisements. Discrepancies between documents matter as much as discrepancies on the car.
What to check
- V5C: chassis/commission number, engine number, colour and number of former keepers.
- Old MOT certificates: mileage sequence, and advisories that repeat year after year.
- Invoices and receipts: who did the major work, and when, particularly cooling, chains and heads.
- Old adverts or auction listings: does the car's described history stay consistent over time?
Where it's explained: Buying guide · Auction, dealer or private
Order or inspect the Heritage Certificate
This is the step that settles it. The BMIHT record lists the engine number, body number, original colour and trim, and the build and dispatch dates for that commission number. If the seller already has one, read it against your own notes; if not, a certificate can be ordered against the commission number, and a serious seller will not object to you waiting for it.
What to check
- The certificate is for this commission number, and is the original document rather than a photocopy of a photocopy.
- Engine number and body number on the certificate against the numbers you read on the car.
- Original colour and trim against the paint and trim codes on the commission plate.
- Build and dispatch dates against the year claimed for the car.
Where it's explained: Matching numbers & the Heritage Certificate · Clubs who can help resolve a query
Decide what any mismatch is worth
A non-original engine, a replaced body panel or a swapped gearbox does not make a car a bad buy, a well-sorted non-matching Stag is often a better car than a tired original. It does, however, change what it is worth. Take the findings into the buying guide and what a Stag costs before agreeing a price.
What to check
- List every mismatch you found, and whether each is documented or simply unexplained.
- Separate originality questions from condition questions, they affect value differently.
- Compare the asking price with current price bands for the car's actual condition and specification.
Where it's explained: What a Stag costs · Market report · Price tracker
Where a number cannot be read, or the paperwork and the car disagree, the Stag Owners Club and the British Motor Industry Heritage Trust are the places to resolve it: not the seller's recollection.
Frequently asked questions
Where exactly is the engine number stamped?
On very early cars it sits on a cast boss between the two rearmost spark plugs on the left-hand cylinder bank. From October 1971 it was moved to the back of the block, between the distributor and the bellhousing, where it is easier to read with a torch and a mirror.
What does a matching-numbers Stag mean?
It means the engine number and body number on the car match the numbers the factory recorded against the commission number. The definitive proof is a British Motor Industry Heritage Trust certificate, which lists the original engine, body, colour and trim.
Can I tell a US Federal Stag from the engine number alone?
Usually yes. US Federal cars carry an LE prefix (early cars used LD), while cars for all other markets carry LF. A suffix U or C points to emissions equipment. Always cross-check with the commission plate and the Heritage record. There is more on American cars, emissions and lighting equipment, importing and titling, on our US Federal-spec page.
Where is the body number found?
On a small plate fixed to the front body crossmember, beside the left-hand bonnet hinge. It begins T 001 LD and is useful only as an originality cross-check, not for ordering parts.
Should the engine number match the commission number?
Not exactly. The two numbers are from different sequences, but they should be in the same general era. A later engine in an early car, or a non-Triumph V8, is the first thing a buyer should investigate. The Heritage Certificate will settle the question definitively.