The original MG T-Series gearbox is a four-speed with a direct top gear. On the road, that means the XPAG turns over hard at motorway speeds — around four thousand revs at sixty in a standard TD or TF. A five-speed conversion is the single change that most transforms the car's usability, and the Ford Type 9 has become the near-universal choice.
Why fit a five-speed?
The XPAG and XPEG engines were designed for a country of narrow lanes and modest cruising speeds. In direct fourth on the standard 4.875:1 back axle, sixty miles per hour asks the engine for roughly 4,000 rpm. It will do it all day — the bottom end is stout — but the car is noisy, the oil gets hot, and any long run becomes an event rather than a journey.
A Ford Type 9 gearbox provides an overdrive top with a ratio around 0.82:1. Fitted behind an unchanged XPAG and back axle, that drops engine speed at sixty by roughly eighteen per cent — down from around 4,000 rpm to about 3,300. The car pulls at a relaxed gait, uses less fuel on a run, and the driver arrives less tired. First through fourth remain close to the original ratios, so town driving and hill starts are unchanged.
The Ford Type 9 in brief
The Type 9 is a longitudinal five-speed manual gearbox that Ford of Britain fitted to the Sierra, Capri and Granada from 1982 into the 1990s. It is compact, cheap in the used market, well understood by rebuilders, and its input shaft is easily adapted to a Borg & Beck 8-inch or 7¼-inch clutch of the type MG used. Its ratios — with a direct fourth and an overdrive fifth around 0.82:1 — suit the T-Series axle almost exactly.
There are three broad Type 9 variants (Sierra 1.6, 2.0 and 2.3/2.8). The 2.0-litre "long tail" from a Sierra is the one specialists usually build up, because it is the strongest of the family, uses widely available synchros and bearings, and has the longest gearbox extension for a shorter propshaft. A specialist rebuild — fresh bearings, uprated synchros, new seals — is the sensible starting point; a rough breaker's-yard box is not.
The two mainstream UK kits
Two UK specialists dominate the T-Series conversion market. Both supply an engineered kit rather than a bag of parts, and both have been refined over decades.
::: Hi-Gear Engineering (Nottinghamshire) — long-established supplier of Type 9 conversion kits for the MG T-Series, MGA and MGB. Their kit typically comprises a machined bell-housing adaptor, a spigot bush for the input shaft, a modified or new gear-lever, clutch actuation provisions, and detailed fitting notes. The gearbox itself is supplied rebuilt. :::
::: Vitesse Global (formerly Vitesse Racing, Cambridgeshire) — an equally established specialist offering Type 9 conversions for the same range of British sports cars. Their kit follows the same broad pattern: adaptor plate, spigot bearing, remote gear-change linkage and clutch details. Both firms will build the box to order and both quote fitting to their own workshops as an option. :::
The two kits do the same job by slightly different engineering routes. Detailed differences — exactly where the gear-lever falls to hand, how the clutch is actuated, whether the propshaft is shortened at the customer's end or supplied ready-made — are small in isolation but matter when it comes to fitting. Before you commit, telephone both firms and ask each of them the same three questions: what is included, what the customer supplies, and what tunnel modification (if any) is required for your specific chassis.
::owner-note There is no ''best'' kit in the abstract. There is the kit whose engineering the customer's fitter is familiar with, and the kit for which local support is available. Both suppliers are respected. Choose on service, not on brochure copy. ::
Cruising RPM — what actually changes
The number that matters is engine speed at a chosen cruising speed. The table below shows the position for a TD or TF on a standard 4.875:1 back axle and typical 5.60 × 15 tyres. Figures are approximate.
| Gear | Ratio | Engine RPM at 50 mph | Engine RPM at 60 mph |
|---|---|---|---|
| Standard 4th (direct) | 1.00 | ~3,350 | ~4,000 |
| Type 9 5th (overdrive) | 0.82 | ~2,750 | ~3,300 |
The change is felt more than it is heard. The engine is not straining at 4,000 rpm — an XPAG in good order will happily sit there — but at 3,300 it is loafing, and the difference over a hundred-mile run is dramatic. Fuel consumption typically improves by two to four miles per gallon on a steady run. Nothing else in the car is stressed less; the axle and engine work exactly as before at any given road speed. The five-speed simply lets the driver hold a higher road speed without holding a higher engine speed.
TF 1500 owners fitted with the taller 4.55:1 back axle are already partway there in standard form. A Type 9 conversion still pays back, but the improvement is proportionally smaller — cruising drops from around 3,750 rpm to around 3,100 rpm at sixty.
Installation — what the work involves
A Type 9 conversion is not a bolt-on afternoon job. It is a competent weekend's work for an experienced amateur, or a day and a half in a professional workshop. The kits are engineered — nothing has to be fabricated — but the sequence matters.
- Remove the original gearbox, propshaft and gear-lever. Drain and set aside; the original box has resale value if it is sound.
- Fit the bell-housing adaptor to the rebuilt Type 9 with the supplied fasteners; check spigot alignment.
- Fit the spigot bush to the crankshaft; check that the clutch friction plate is the correct diameter and spline count for the Type 9 input shaft (the kits specify).
- Offer the assembled gearbox up to the engine on a trolley jack. Bolt up.
- Fit the new gear-lever assembly to the extension housing. On some kits the lever exits through the original tunnel aperture unmodified; on others a small tunnel modification is required. Check before committing metal.
- Shorten the propshaft to the length specified by the kit supplier, or fit the new propshaft they supply. Balance is worth the small extra cost.
- Refit clutch actuation — cable or hydraulic, per the kit — and bleed if hydraulic.
- Refill with the specified gear oil (usually a modern ATF or a light EP oil — the supplier will state which).
::: warning Do not modify the tunnel until the gearbox is fully home and the gear-lever position has been checked in every gear. Cutting a hole first, on the assumption that it will be needed, is a common and expensive error. :::
The UK "substantial change" test
For a UK-registered T-Type over forty years old, the MOT exemption and the historic tax class both hinge on the vehicle not having undergone a "substantial change" in the previous thirty years. The DVLA and DVSA guidance sets out a point-based test that assesses the chassis, the suspension, the axles and the engine — with the body considered separately for coachbuilt cars.
The gearbox is not one of the assessed items. A Type 9 conversion, on its own, does not count as a substantial change under the current guidance. The car remains eligible for MOT exemption (if the owner declares it so) and remains in the historic tax class. Fitting a five-speed gearbox is therefore one of the least paperwork-sensitive drivability upgrades available on a T-Type.
If in doubt, work through the interactive quiz below with your specific car in mind. A gearbox swap alone should return a comfortable pass.
Chassis
Has the chassis frame been replaced or modified in the last 30 years?
A new frame to the original pattern, or repair sections welded in, is not the same as changing to a different chassis design.
Reversibility and originality
The strongest argument for the Type 9 conversion — beyond the driving benefit — is that it is entirely reversible. Both kits bolt the adaptor plate to the standard engine using existing bell-housing threads; nothing on the engine or chassis is modified. Keep the original gearbox, propshaft and gear-lever in your garage, dry and greased. If a future owner or a future concours event calls for standard specification, an experienced fitter can reverse the conversion in a day.
That is not true of every "improvement" made to a T-Type. It is one reason serious enthusiasts, including several who show their cars regularly, will fit a Type 9 without hesitation.
What we recommend
For a driver's TD or TF that will see distance work, the Type 9 conversion is the single best-value change available. Fit it once, fit it properly, and enjoy fifteen years of relaxed motorway cruising with an engine loafing at three thousand three hundred revs. For a concours car, or a car that will only ever do local shows, the standard four-speed remains correct — and there is nothing wrong with an XPAG at four thousand revs for twenty miles at a time.
Whichever kit you choose, budget for the gearbox to be professionally rebuilt before it goes in. Fitting a tired Type 9 to save a few hundred pounds is a false economy — the box is the whole point of the conversion, and its condition governs how the car will feel for the next decade.