MG T-Series Chassis & Engine Number Identification: The Complete Guide

Two numbers tell the whole story of a T-Type, where to find them, how to read them, and what the codes mean.

Every MG T-Series left Abingdon with two identity marks the factory expected you to be able to find and cross-check: a chassis (car) number stamped into the frame, and an engine number on a plate on the engine itself. Together they tell you which model you are looking at, roughly when it was built, and, with a little decoding, how it left the works. This guide walks through where to find both numbers, how to read the chassis ranges by model, how to decode the TF's Nuffield car number, what the engine prefixes mean, and what to make of a replacement engine.

Reference information adapted from the MG Car Club T Register; verify your car's details with the T Register and the MG factory records held at the British Motor Museum.

Where to find the numbers

Two places to look, and they should agree.

Chassis number. Look at the near-side (left-hand as you face the front of the car) dumb-iron, the forward chassis extension the bumper mounts to. The chassis number is stamped directly into the metal. It is then repeated on a small identity plate riveted under the bonnet, typically on the battery/tool box or bulkhead. The stamped number and the plate should match; if they don't, you are looking at a car that has had frame or bulkhead work done at some point.

Engine number. On the TA, TB and early TC the engine number lives on a plate riveted to the left-hand side of the flywheel housing. The plate itself is worth noticing: an octagon, circle or square carrier with a small central brass disc that identifies the engine type. Later TCs and every TD and TF moved the engine number to a shallow machined plinth on the forward right-hand side of the block, where the number is also stamped directly into the plinth alongside the plate.

Always cross-check the two. Because these cars are now seventy or more years old and have passed through many hands, mismatched engines are common, a car with an original chassis and a period-correct but non-matching replacement engine is a perfectly normal thing to encounter, and not necessarily a mark against it. What you want to know is what you are actually looking at.

Chassis numbers by model

Chassis numbers on the pre-TF cars run as plain numbers, without a model prefix on the frame itself. Approximate production ranges are:

A historian's caveat: the very first numbers in each series (0251 or 0252) were prototypes and are not generally counted as production cars.

TD variants: what "Mark II" and "TD2" actually mean

The TD is the model most often muddled by owners and by adverts, so it is worth being precise. There are two things that can look like the same thing and are not.

TD/C, or "Mark II". A factory competition-oriented variant of the TD with larger valves, larger carburettors and stiffer front suspension. It is a specification, distinguishing car from car.

"TD2" (as in the engine code XPAG/TD2/). A production change to the engine, not a competition spec. The TD2 code identifies the engines built after the introduction of the larger 8" clutch around chassis number 10000, in mid-1951. A perfectly ordinary, non-competition TD from late 1951 onwards will normally have a "TD2" engine number and is not a Mark II.

Two different things, two different meanings.

TD export codes

Export TDs also carry codes on the identity plate reflecting how they were shipped:

• EXR, export, right-hand drive.
• EXL, export, left-hand drive.
• EXLU, later EXL/NA and then EXLNA, the North-American specification LHD car as it evolved through production.

TF: Nuffield car numbers

The TF adopted the group-wide Nuffield car-numbering system used across Morris, MG and their sister marques. After two prototypes the sequence began at 501 and ran to 10100, comprising roughly 6,200 TF1250s and 3,400 TF1500s. On the chassis itself the stamping is normally prefixed TF; on the identity plate the number is the Nuffield car number and encodes rather more information than an early chassis number ever did, see the decoder below.

Decoding the TF Nuffield car number

The TF identity plate carries a car number in the form of two letters, then a first digit, then a second digit, then the sequential build number, for example HDP 15 xxxx. Each element means something specific.

Body type and colour (the two letters)

The first pair of letters describes the body type and factory colour.

First digit, market and drive

Second digit, finish

Worked example

A TF whose plate begins HDP 13 xxxx reads as: HD body (MG two-seater), P for Ivory, first digit 1 for UK right-hand drive, second digit 3 for full cellulose finish. In plain English: a UK-market, right-hand-drive, Ivory TF, fully cellulose painted.

Two small things to keep in mind. The identity plate carries the Nuffield car number; the chassis stamping on the frame is normally the TF prefix plus the sequential build number, and the two point to the same car. CKD (completely knocked-down) or partially-assembled export cars can carry additional letters from the Morris-standard scheme reflecting their shipped state, so an unfamiliar extra letter on a TF plate is not necessarily wrong. Treat any decode as an indicative guide and confirm with the T Register or the factory records.

Engine numbers and what the prefix tells you

The engine-number prefix identifies the engine type and, for XPAG-engined cars, the specific evolution the block represents. At the highest level:

Within the XPAG family, the T Register's ongoing work identifies distinct sub-types by the number-prefix carried on the plate, which reflects two production changes, clutch size (7¼" or 8") and water-jacket porting (oval or round water holes).

Two useful footnotes. Export LHD cars often carry an extra code LHX appended to the engine number (for example XPAG/TD/LHX …); this normally appears on the bulkhead identity plate rather than on the engine plate itself. And because the MG Y-type saloon and tourer shared the same basic XPAG unit in a milder state of tune, Y-type engines occasionally end up in T-Types and vice versa; their prefixes follow a related but distinct scheme, so an unexpected Y-related code is worth investigating rather than dismissing.

Replacement engines and casting numbers

Many surviving T-Types no longer wear the engine they left Abingdon with. Morris Motors and later BMC supplied factory-exchange "Gold Seal" replacement engines throughout the T-Series's usable life, and any car that saw hard use, as most did, is a candidate to have received one.

A replacement engine is easy to identify by its plate. Instead of the octagonal or circular XPAG plate the car was built with, it typically carries a square "replacement engine" plate with a letter prefix (letters recorded to date include A, B, C, E, G and RS) followed by a longer serial number. The original engine number is sometimes still to be found stamped directly into the block near the plate, if a previous owner has not filed or dressed it away, worth a careful look with a torch and a wire brush.

Casting numbers and date codes

Beyond the identity plate, the block and head carry raw casting information from the foundry. On XPAG and XPEG blocks the casting number is generally found near the dipstick tube; on the head, similar casting information sits toward the rear. Small features such as the "W-in-a-diamond" foundry mark appear on later blocks and heads, and the T Register has done extensive work correlating casting numbers, date codes and foundry marks to build periods. The blocks themselves were cast at the Wellingborough Ironworks.

The complete casting-number picture is much more detail than belongs in this guide. For serious dating and originality work, the T Register's ongoing casting-number research is the reference to use.

More on the plates and numbers

The body number. Alongside the chassis and engine numbers there is a body number, carried on a separate plate and stamped into the ash frame. If the chassis, engine and body numbers agree with each other and with the factory record, the car is what it says it is.

The TD engine sequence. Early TD engines run from XPAG/TD/501 to XPAG/TD/9407. The prefix becomes XPAG/TD2 at engine 9408, in July 1951, and Competition Model engines carry XPAG/TD3 from June 1952. TF 1500 numbering starts at XPEG 501. The related Y-type saloons used XPAG/SC, and the YT tourer XPAG/TL or XPAG/TR.

Replacement blocks. A replacement block may even have begun life in a TD, a YB or a Wolseley 4/44, so a block with an unexpected history is not necessarily wrong for the car, only different from how it left Abingdon.

Two further plate codes. Barrie Jones's key to the TD and TF plate adds two market digits not shown in the table above, 5 for CKD right-hand drive and 6 for CKD left-hand drive, and gives H as the colour letter for primer. It also notes that cellulose (3) was normal on green cars and a cellulose body with synthetic wings (6) normal on everything else. Source: Barrie Jones, MG TD, TF & TF1500: 1949–1955, The Essential Buyer's Guide, Veloce Publishing, ISBN 978-1-845843-52-6, page 57. The codes changed in detail through production, so read a particular plate against the factory record before relying on it.

Which record covers which car. The British Motor Museum holds factory records for MGs built from 1953, beginning with the TF, and its Heritage Certificate gives a TF's build and despatch dates, engine and body numbers, colour scheme and factory-fitted equipment; its certificates do not cover the TA, TB, TC or TD. For those cars, the MG Car Club T Register's Factory Production Records are the factory record, searchable by chassis or engine number. For a TF the two can be read together.

Why it matters, and how to verify

Matching numbers matter for two reasons. Originality and value: a car whose chassis, bulkhead plate and engine number all agree, in the correct format for the model, is more valuable, and more informative, than a car that has been re-engined or rebadged over the years. Historical accuracy: knowing exactly what you have (a genuine TD Mk II, a TF1500 rather than a TF1250, an original XPAG rather than a Gold Seal replacement) lets you set the car up correctly and describe it honestly.

That said, a T-Type that has had a replacement engine along the way is a perfectly normal thing. These are cars meant to be driven; a sound, correct-family Gold Seal XPAG in a TC is not a problem, only a fact about the car. What matters is knowing.

For definitive verification of a specific car's history there are two authorities to consult:

• The MG Car Club T Register, custodians of the community-held knowledge on chassis and engine numbers, casting numbers and variants, visit mgcc.co.uk.
• The MG factory records, held at the British Motor Museum at Gaydon, which can confirm the original build details of a car by its chassis number.

If you have decoded your own T-Type from this article, please add it to the Registry, every submission strengthens the record for the next owner.

Related reading

For the coachwork side of identifying and looking after a T-Type, see the MG T-Series Bodywork pillar article. For a walk through each model as a whole, The Models is the place to start; the Registry collects owner-submitted cars decoded exactly as described above.

Frequently asked questions

Where is the chassis number on an MG T-Type?

Stamped into the near-side (left-hand) dumb-iron, the forward chassis extension the front bumper attaches to, and repeated on a small identity plate riveted under the bonnet, typically on the battery/tool box or bulkhead. The stamping and the plate should match.

What engine does an MG TF1500 have?

The XPEG, an enlarged 1,466 cc development of the XPAG used in every other T-Type from the TB to the TF1250. TF1500 engine numbers are prefixed XPEG; a TF with an XPAG/TF/ prefix is a TF1250.

What does XPAG mean?

XPAG is the factory code for the T-Series' 1,250 cc four-cylinder overhead-valve engine, used in the TB, TC, TD and TF1250 (and in the sister MG Y-type saloon and tourer). XPEG is the 1,466 cc TF1500 development of the same basic unit.

How do I decode an MG TF car number?

Read it in four parts: the letters (body type and colour, HD is the MG two-seater, followed by A/B/C/E/P for Black, Light Grey, Dark Red, Mid Green or Ivory); the first digit (market/drive, 1 UK RHD, 2 export RHD, 3 export LHD, 4 North America LHD); the second digit (finish, 3 cellulose, 5 primer, 6 cellulose body with synthetic wings); and finally the sequential build number.

How do I tell a TF1250 from a TF1500?

By the engine-number prefix on the engine plate. A TF1250 carries XPAG/TF/; a TF1500 carries XPEG. Externally the two look almost identical, so the engine number is the reliable answer.

What is a TD Mark II?

The factory competition-oriented TD/C, with larger valves and carburettors and stiffer front suspension. It is a car-level specification, not an engine code, do not confuse it with the TD2 engine prefix, which simply marks the introduction of the larger 8" clutch in mid-1951 and applies to ordinary TDs as well.