Daimler XJS: Which Version Should You Choose?
The Daimler XJS catalogue covers one Coupe generation produced from 1973 to 1977, with four versions: 4.2 MT, 4.2 AT, 5.3 MT, and 5.3 AT. The decisive choice is between two naturally aspirated Gasoline engines and two transmission types. The 4.2 versions produce 173 hp and 306 Nm, while the 5.3 versions deliver 289 hp and 390 Nm. That gives the larger engine 116 hp and 84 Nm more.
The Daimler XJS catalogue covers one Coupe generation produced from 1973 to 1977, with four versions: 4.2 MT, 4.2 AT, 5.3 MT, and 5.3 AT. The decisive choice is between two naturally aspirated Gasoline engines and two transmission types. The 4.2 versions produce 173 hp and 306 Nm, while the 5.3 versions deliver 289 hp and 390 Nm. That gives the larger engine 116 hp and 84 Nm more. Buyers then choose either a 4-speed Manual or a 3-speed Automatic, with RWD standard across the range.
Daimler XJS generations compared
There is only one Daimler XJS generation in the supplied catalogue, so there is no choice between generations or evidence of a generational change to compare. The 1 generation ran from 1973 to 1977 as a Coupe and contained four versions. All four share the same production period, RWD, independent spring front suspension, ventilated disc front brakes, disc rear brakes, and 120 mm ground clearance.
Because every version belongs to the same generation, the buying decision comes down to engine output and gearbox rather than body style or production phase. The data contains no separate restyling, later generation, or alternative body type.
Engine specs and version comparison
| Version | Power | Torque | Displacement | Fuel | Cylinders | Layout | Boost | Gearbox | Drive |
|---|---|---|---|---|---|---|---|---|---|
| 4.2 MT | 173 hp | 306 Nm | 4,235 cm³ | Gasoline | 6 | Inline | No | 4-speed Manual | RWD |
| 4.2 AT | 173 hp | 306 Nm | 4,235 cm³ | Gasoline | 6 | Inline | No | 3-speed Automatic | RWD |
| 5.3 MT | 289 hp | 390 Nm | 5,343 cm³ | Gasoline | 12 | V-shaped | No | 4-speed Manual | RWD |
| 5.3 AT | 289 hp | 390 Nm | 5,343 cm³ | Gasoline | 12 | V-shaped | No | 3-speed Automatic | RWD |
The 4.2 MT and 4.2 AT use the same 4,235 cm³ Inline 6-cylinder Gasoline engine. It has 4 valves per cylinder, distributed injection (multi-point), and no boost. Output is 173 hp at 5,000 rpm, while peak torque is 306 Nm at 3,500 rpm. The only recorded mechanical choice between these versions is the gearbox: the 4.2 MT has a 4-speed Manual, whereas the 4.2 AT has a 3-speed Automatic.
The 5.3 MT and 5.3 AT share a 5,343 cm³ V-shaped 12-cylinder Gasoline engine with 2 valves per cylinder, distributed injection (multi-point), and no boost. It produces 289 hp at 5,750 rpm and 390 Nm at 3,500 rpm. The 5.3 MT pairs it with a 4-speed Manual; the 5.3 AT uses a 3-speed Automatic.
The 5.3 engine has 1,108 cm³ more displacement than the 4.2 engine, an increase of about 26%. Its 289 hp represents about 67% more power than the 4.2 engine’s 173 hp, while its 390 Nm is about 27% greater than the 4.2 engine’s 306 Nm. In output per litre, the 4.2 versions provide about 40.9 hp per litre and the 5.3 versions about 54.1 hp per litre. The 5.3 therefore offers roughly 13.2 additional hp per litre.
Peak torque arrives at 3,500 rpm with both engines. Peak power arrives at 5,000 rpm in the 4.2 versions and 5,750 rpm in the 5.3 versions, a difference of 750 rpm.
Performance, top speed, and mpg
| Version | 0–100 km/h | Top speed | City consumption | Highway consumption | Combined consumption |
|---|---|---|---|---|---|
| 4.2 MT | not measured | not measured | not measured | not measured | not measured |
| 4.2 AT | not measured | not measured | not measured | not measured | not measured |
| 5.3 MT | 7.8 seconds | 237 km/h | not measured | not measured | not measured |
| 5.3 AT | not measured | not measured | not measured | not measured | not measured |
The 5.3 MT is the only version with measured acceleration and maximum-speed figures: it reaches 100 km/h in 7.8 seconds and has a top speed of 237 km/h. Acceleration and top speed are not measured for the 4.2 MT, 4.2 AT, or 5.3 AT, so their real-world performance cannot be ranked from the supplied figures.
Fuel consumption is not measured for any version. City, highway, and combined consumption—and therefore mpg—are all not measured. CO₂ output and ecological class are also not measured across the range. The engine specifications alone do not provide a valid basis for inventing economy figures.
Dimensions, weight, and ground clearance
| Version | Kerb weight | Gross weight | Ground clearance | Tank | Wheel sizes |
|---|---|---|---|---|---|
| 4.2 MT | not measured | not measured | 120 mm | not measured | not measured |
| 4.2 AT | not measured | not measured | 120 mm | not measured | not measured |
| 5.3 MT | 1,778 kg | not measured | 120 mm | not measured | not measured |
| 5.3 AT | not measured | not measured | 120 mm | not measured | not measured |
Only the 5.3 MT has a measured kerb weight, at 1,778 kg. With 289 hp, that equals approximately 6.15 kg per horsepower, or about 162.5 hp per tonne. Kerb weight is not measured for the other three versions, so no honest weight-per-horsepower comparison can be made between them.
Gross weight, fuel-tank capacity, and wheel sizes are not measured for any version. Ground clearance is consistently listed as 120 mm for the 4.2 MT, 4.2 AT, 5.3 MT, and 5.3 AT.
Reliability and problems
Reliability records and model-specific problem data are not measured for any Daimler XJS version in the supplied catalogue. There is therefore no numerical basis here for ranking the 4.2 MT, 4.2 AT, 5.3 MT, or 5.3 AT by reliability, maintenance burden, or repair frequency. The available comparison is limited to engine, transmission, performance, chassis, and recorded weight specifications.
Which Daimler XJS version should you buy?
Choose the 4.2 MT if you want the lower-output engine with the 4-speed Manual. It combines 173 hp and 306 Nm with RWD and gives the Manual one more forward gear than the 3-speed Automatic fitted to the 4.2 AT. Its acceleration, top speed, kerb weight, and fuel consumption are not measured.
Choose the 4.2 AT if an Automatic is more important than having the 4-speed Manual. It retains exactly the same recorded engine figures as the 4.2 MT—4,235 cm³, 173 hp, and 306 Nm—but uses a 3-speed Automatic. The data does not establish a performance, economy, or weight penalty for that transmission because those figures are not measured.
Choose the 5.3 MT when maximum documented performance is the priority. It offers 289 hp and 390 Nm, exceeding either 4.2 version by 116 hp and 84 Nm. It is also the only version backed by measured performance figures: 7.8 seconds to 100 km/h and 237 km/h. Its 1,778 kg kerb weight is the only measured weight in the range, producing a calculated ratio of about 6.15 kg per horsepower.
Choose the 5.3 AT if you want the higher-output 5,343 cm³ engine with a 3-speed Automatic. Its engine matches the 5.3 MT at 289 hp and 390 Nm, but its acceleration, top speed, kerb weight, and consumption are not measured. Consequently, it cannot be assumed to equal the 5.3 MT’s recorded 7.8-second acceleration or 237 km/h top speed.
On the available evidence, the 5.3 MT is the strongest specification-led choice because it combines the highest engine output with the catalogue’s only measured performance results. The 4.2 MT is the clearest alternative for a buyer prioritizing the 4-speed Manual without requiring 289 hp, while the 4.2 AT and 5.3 AT serve buyers whose defining requirement is the 3-speed Automatic. Price data is unavailable, so the extra financial cost of either 5.3 version—and whether its additional 116 hp and 84 Nm represent good value—cannot be measured.