Gearbox Conversions
Elevate your vehicle’s performance and driving experience with our expertly engineered 6-speed manual and ZF 8-speed automatic transmission conversions. Designed to deliver unmatched precision and responsiveness, these upgrades put you at the centre of the driving experience.
Our conversions go beyond just performance—featuring custom mapping for optimised power delivery, enhanced fuel efficiency, and greater power transfer to the wheels. Whether you’re looking to maximise your car’s potential on the road or unlock new levels of versatility, our solutions open up a world of possibilities, redefining the way you drive.
Manual Conversion -
The ultimate upgrade for the X100 model range
Bringing the perfect balance of engaging driving, power and responsiveness. The manual conversion package is the result of an extensive research and development program and gives you everything you need to convert your XK to a manual gearbox, it utilises the Jaguar six speed ZF manual transmission as well as quite a few components that need replacing to complete this conversion to a fully working and compliant kit.*
Transmission losses through auto boxes are substantial, with roughly 40-50BHP lost before reaching the rear wheels the XK was on the back foot against its competitors from the get go. By removing the slush box and moving to a mechanical driveline these previous losses are translated directly to the wheels, coupled with extra performance related parts the car is then able to put down roughly 450bhp on supercharged cars and 350bhp on N/A engines (More with other supporting mods).
The biggest complication with manual conversions on the XK and main difference in our kits is the electronics. Due to Jaguar not designing the XK as a manual there is no way for the original electronics to function correctly without attempting to trick the original ECU, We have found this method to be very limited and cause various other complications across the car.
The original engine ECU’S are outdated so we have invested in completely replacing the factory version with our own standalone Maxx Race ECU, This package will fully integrate and replace the stock ECU. We have developed over many years the ability to completely replicate the original CAN data so your vehicle will still have all of the OEM features but with the huge benefits of having complete tuning control, offering a large number of extras such as wide band lambda control etc this also opens up further tuning modifications and flexibility for more power going forward such as boost, fuel supply and major engine changes to timing and compression etc.
Modifications need to be made to the various areas of the car in order to give adequate clearance for items such as the new gearbox, this requires replacement of the catalytic converters due to bell housing clearance. However this future proofs the car from CAT failure in the future as early cars CAT’s are blocking more frequently now due to age. As a natural by product a more free flowing CAT will allow the car to expel exhaust gases quicker in order to produce more power throughout the rev range and in particular the mid range.
The interior of the car remains largely unchanged with the exception of the extra pedal from our SR Custom pedal box and shifter assembly. The short shifter and linkages has been engineered and raised slightly to allow for proper clearance on the centre console and reducing the distance from the gear knob to the steering wheel, this allows for a far more engaging drive and minimal shift time. SR have developed and fabricated a bespoke pedal assembly to give correct pedal spacing and adequate footwell space, finished with alloy pedals to keep a clean theme throughout.
The flexibility of the ECU allows for utilisation of supporting mods such as supercharger pulleys and larger injectors at this point or further down the line while eliminating possible future issues with the aged technology of the original ECU (In some cases nearly 30 years old now), please let us know if you would like to add these to the package while the car is being tuned for maximum results and performance.
The conversion process is carried out out our facility here at Swallows Racing and can be typically completed within four weeks from delivery to our facility.*
The full conversion kit consists of –
- ZF6 Manual 6 Speed Gearbox
- Custom TTV Clutch Cover
- Custom TTV Clutch Plate (Power and use dependant plate for individual car)
- Custom Billet TTV Flywheel
- SR 300 cell sports cats
- Custom Propshaft
- Gearbox Mount
- Slave Cylinder
- Custom Gear Linkage and Shifter
- Custom Clutch Lines
- Custom Gear Knob
- Interior Trim Surround and gator
- SR Custom Pedal Box and alloy pedals
- Stand Alone Maxx ECU Conversion and Custom Loom
- Bespoke Dyno Tuning
From £8,795+vat – Available spring 2025
*Only available in RHD
"Its a hot rod, it’s a muscle car, Im more conscious of attacking corners in it, im more conscious of exploiting the qualities of that platform underneath, it does encourage you to exploit what is really a fine handling car that was lost because of the slush box, its a totally different beast and Jaguar should have made it"
ZF8 Conversion -
The NEW new..
Bringing the drivability of the modern day Jaguars to the ZF5 and ZF6 speed generation vehicles, this conversion is perfect for those who want performance, fuel economy and more control of their car while critically maintaining their auto transmission set up. The ZF8 gearbox allows for a more up to date driving style to be used giving benefits to all aspects of the cars drivability, and bringing your Jag up to modern standards making it one of the best upgrades available.
With more gears at your disposal the natural by product is a faster accelerating and more economical car, our 8 speed packages have been developed out of how impressive the ZF box is for both response and smoothness through the gears. Couple this with the ability to configure and map the box in the best way for you and it becomes one of the best mods you can do to the car.
The standard GSM in the car is replaced with a 6 button CAN key pad (PDM) in order to control the gear changes much like the J-Gate and the twist knob selectors, the key pads are then set into the position of the existing selectors with a custom surround housing to keep things neat and clean while giving maximum visibility to see the PDM.
Utilising the Maxx mini to control and gearbox allows us to map the box for a variety of different purposes, for example if fuel economy is something you are looking to achieve then letting the box change up earlier getting you into a higher gear faster would be used.
However if performance is something you are looking to achieve then we can map the gearbox so that gear changes are fast and punchy with them occurring high in the rev range to maximise the torque and power delivery through each gear.
Conversions are carried out using low mileage remanufactured boxes, we also fit a new sump filter, electrical seal to the box and fresh ZF lifeguard 8 oil too. Other than the gearbox controller (GSM) the installations are carried out with minimal cosmetic differences to the car in order to keep as much originality as possible.
The conversion process is carried out out our facility here at Swallows Racing and can be typically completed within 1 week from delivery to our facility.
The full conversion consists of –
: ZF8 Remanufactured gearbox with new sump filter, electrical seal and ZF Lifeguard 8 oil
: Conversion adapter plate
: Maxx mini ECU gearbox controller
: SR/ Maxx gearbox integration loom
: 6 button CAN key pad
: Interior key pad surround
: SR Custom Map
From £4,449+vat – Available Autumn 2025
The mod I never knew could make such a dramatic difference to the drivability of my car, from day to day driving and getting much better fuel economy, up to performance driving where the car is more urgent and eager to accelerate. This has made me fall in love with my car again.
