Jaguar Mark IX: Which Version to Choose
The Jaguar Mark IX offers a straightforward choice between two versions: 3.8 AT and 3.8 MT. Both are Sedan versions from the model’s only generation, produced from 1958 to 1961. They share the same 3,781 cc Gasoline engine, 220 hp output, 164 kW rating, Inline 6-cylinder layout, carburetor system, and RWD drivetrain.
The Jaguar Mark IX offers a straightforward choice between two versions: 3.8 AT and 3.8 MT. Both are Sedan versions from the model’s only generation, produced from 1958 to 1961. They share the same 3,781 cc Gasoline engine, 220 hp output, 164 kW rating, Inline 6-cylinder layout, carburetor system, and RWD drivetrain. The decisive difference is the transmission: the 3.8 AT has a 3-speed Automatic, while the 3.8 MT has a 4-speed Manual. Choose the 3.8 AT if an Automatic gearbox and measured performance figures matter most; choose the 3.8 MT if you specifically prefer a Manual gearbox with one more forward gear.
Jaguar Mark IX generations compared
There is only one Jaguar Mark IX generation in the supplied catalogue data, so there is no meaningful choice between generations. The 1 generation ran from 1958 to 1961, used the Sedan body style, and included two versions: 3.8 AT and 3.8 MT.
No separate restyling or alternative body type is listed. Consequently, the buying decision is entirely between the two transmissions rather than between different generations, production periods, or body configurations.
Jaguar Mark IX engine and specs
The 3.8 AT and 3.8 MT have identical engine specifications. Each uses a 3,781 cc Gasoline engine with 6 cylinders in an Inline layout and 2 valves per cylinder. Output is 220 hp or 164 kW, which works out to approximately 58.2 hp per litre. Both versions have a compression ratio of 8 and a bore-and-stroke measurement of 87 × 106.
The engine position is listed as Front, transverse, and the fuel system is Carburetor. Boost is not measured for either version. Both send power through RWD.
| Version | Power | Torque | Displacement | Fuel | Cylinders | Layout | Boost | Gearbox | Drive |
|---|---|---|---|---|---|---|---|---|---|
| 3.8 AT | 220 hp / 164 kW | not measured | 3,781 cc | Gasoline | 6 | Inline | not measured | 3-speed Automatic | RWD |
| 3.8 MT | 220 hp / 164 kW | not measured | 3,781 cc | Gasoline | 6 | Inline | not measured | 4-speed Manual | RWD |
Neither version offers a power advantage: the difference is 0 hp, 0 kW, and 0 cc. The 3.8 MT provides one more forward gear than the 3.8 AT, while the 3.8 AT provides the only Automatic transmission in the range.
Both versions also use Independent, torsion front suspension and Disc front and rear brakes. Rear-suspension specifications are not measured.
Jaguar Mark IX performance and mpg
The 3.8 AT is the only version with measured performance figures in the supplied data. It accelerates from 0 to 100 km/h in 11.3 seconds and reaches a top speed of 184 km/h.
Acceleration and top speed for the 3.8 MT are not measured. This means the shared 220 hp output cannot be used to claim that the Manual is quicker or faster. The 3.8 AT is the stronger choice for a buyer who wants documented performance because it is the only version whose acceleration and maximum speed are recorded.
| Version | 0–100 km/h | Top speed | City consumption | Highway consumption | Combined consumption |
|---|---|---|---|---|---|
| 3.8 AT | 11.3 seconds | 184 km/h | not measured | not measured | not measured |
| 3.8 MT | not measured | not measured | not measured | not measured | not measured |
Fuel consumption is not measured for either version, so no evidence-based mpg or economy comparison is possible. CO2 output and emissions class are also not measured. Neither gearbox can therefore be presented as the more economical choice from the available figures.
Jaguar Mark IX dimensions and weight
The supplied data does not provide body dimensions for either Jaguar Mark IX version. Kerb weight, gross weight, ground clearance, fuel-tank capacity, and wheel sizes are also not measured.
| Version | Kerb weight | Gross weight | Ground clearance | Fuel tank | Wheel sizes |
|---|---|---|---|---|---|
| 3.8 AT | not measured | not measured | not measured | not measured | not measured |
| 3.8 MT | not measured | not measured | not measured | not measured | not measured |
Because kerb weight is not measured, weight per horsepower cannot be calculated for either version. The catalogue data also provides no basis for comparing payload, clearance, driving range, or wheel fitment.
Which Jaguar Mark IX version should you buy?
Choose the 3.8 AT if you want an Automatic transmission or require measured performance data. Its 3-speed Automatic accompanies the same 220 hp, 3,781 cc Gasoline engine used by the Manual version. Its documented 0–100 km/h time is 11.3 seconds, and its documented top speed is 184 km/h.
Choose the 3.8 MT if a Manual transmission is the priority. Its 4-speed Manual has one more forward gear than the 3-speed Automatic in the 3.8 AT, but it does not add power or displacement: output remains 220 hp, and capacity remains 3,781 cc. Acceleration and top speed are not measured, so the extra gear does not establish a numerical performance advantage.
There is no data-supported reason to choose on engine output, engine size, fuel type, cylinder arrangement, drivetrain, front suspension, or brake specification because these are the same for both versions. Economy cannot separate them because city, highway, and combined consumption are not measured. Dimensions and weight cannot separate them either because the relevant figures are not measured.
The practical conclusion is simple: the 3.8 AT is the evidence-led choice for buyers who value an Automatic gearbox and published performance figures, while the 3.8 MT is the focused choice for buyers who want a 4-speed Manual. No price information is supplied, so it is not possible to calculate what any extra purchase cost would buy or to identify the better-value version on price.