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420G

Production years: 1966 - 1971

In 1966 the Mark 10 was re-badged as the 420G with a modicum of trim changes like new chromed hub caps, a bold centre rib in the radiator grille and some interior trim changes. The model, although running alongside the all new XJ6 when introduced in 1968, was finally dropped from the range in 1971.

MODEL SUMMARY

MODEL TYPE

PRODUCTION DATES

ENGINE RANGE:

0 - 60 MPH:

TOP SPEED:

Mark 10/420G/DS420

1966 - 1971

3.8 Litre Saloon

3.8 Litre Saloon - 9.1 seconds

3.8 Litre Saloon - 119.5 mph

4.2 Litre Saloon

4.2 Litre Saloon - 9.9 seconds

4.2 Litre Saloon - 121.5 mph

420G Technical Specifications

Technical Information

Engine Statistics

3.8 Litre Saloon

4.2 Litre Saloon

Engine (cc)

3781

4235

Bore and Stroke (mm)

87 x 106

92.07 x 106

Compression Ratio

8:1 (7:1/9:1 optional)

8:1 (7:1/9:1 optional)

BHP

265

265

@RPM

5500

5400

Torque (lb ft)

260

283

@RPM

4000

4000

Fuellling

3x SU carbs

3x SU carbs

Engine Performance

3.8 Litre Saloon

4.2 Litre Saloon

Top Speed

119.5 mph

121.5 mph

0 - 60 mph

9.1 seconds

9.9 seconds

Fuel Consumption

14.1 mpg

14.5 mpg

model Specifications

3.8 Litre Saloon

4.2 Litre Saloon

Transmission

4-speed (3 synchro) BW 3-speed auto

4-speed (3 synchro) BW 3-speed auto

Wheel Size (in)

14, steel

14, steel

Suspension (Front)

nd semi-trailing wishbones, coil springs, anti-roll bar

nd semi-trailing wishbones, coil springs, anti-roll bar

Suspension (Rear)

Ind lower wishbone/upper driveshaft link, radius arms, coil springs

Ind lower wishbone/upper driveshaft link, radius arms, coil springs

Brakes

4-wheel disc, rear inboard

4-wheel disc, rear inboard

Model Dimensions

3.8 Litre Saloon

4.2 Litre Saloon

Length (in)

202

202

Width (in)

76

76

Height (in)

54.75

54.75

Wheelbase (in)

120

120

Front Track (in)

58

58

Rear Track (in)

58

58

Weight (Cwt)

37

37

OPTIONAL EXTRAS

  • Choice of three radio installations with or without rear parcel shelf-mounted speaker
  • Electric radio aerial
  • Wind-up radio aerial
  • Electrically operated windows (front and rear)
  • Laminated windscreen
  • Witter tow bar
  • Heated rear screen (earlier cars)
  • Front seat belts
  • Choice of radial, town and country, or whitewall tyres
  • Borg Warner automatic transmission
  • Overdrive (for non-overdrive-equipped manual transmission cars)
  • Fire extinguisher
  • Sundym tinted windscreen and side windows
  • Wing mirrors
  • Integrated ignition/starter switch to steering column
  • Limousine appointments (only available on ordering a new car)

CLUB EVENTS

SHOWS

NEC, Classic Motor Show 2025

  • North Avenue , Marston Green, Birmingham, B40 1NT
  • 7th - 9th NOVEMBER 2025

OTHER

JEC Coffee & Cars At The Piston Club

  • The Piston Club
  • 9th August 2025

TRACKSPORT

Silverstone Festival 2025

  • Towcester, Northamptonshire
  • 22 Aug – 24 Aug

CLUB NEWS

  • Club, Spares

JEC Spares Initiative, an exciting development
  • Club

Will your car pass the detailing test?
  • Club

Jaguar Enthusiasts’ Club Road Show 2019

MODEL CONTACTS

Nigel Thorley

Magazine Editor & Seminars

  • flagshipsaloon@jecmodels.org.uk

Jaguar Enthusiasts' Club Insurance powered by Peter James

Specialists in flexible insurance cover, made to protect the true value of what matters most, Peter James Insurance is best known for its classics and vintage vehicle insurance including specialist options such as Free Agreed Value, Laid-Up Cover, Multi-Vehicle options, Limited Mileage and more. Alongside classic car cover, they have significant expertise and experience in motor trade, commercial, liability and indemnity insurance across a diverse range of sectors, including a club liability insurance scheme – unique to Peter James Insurance.

Get a quick quote online via: https://qqcar.peterjamesinsurance.co.uk/?c=JEC&utm_source=JECQQ&utm_medium=Referral&utm_campaign=zPJI_QQ_JEC

Read more about the scheme here: https://www.peterjamesinsurance.co.uk/club-member/jec/?utm_source=JEC&utm_medium=Referral&utm_campaign=zPJI_JEC

Call: 0121 274 5360

Please contact Jaguar Enthusiasts’ Club Insurance powered by Peter James on 0121 274 5360

Insurance Checklist

Before you get in touch with us please make sure to note down as many of the following details as possible. If you can complete the checklist ahead of time, it’ll make the process of arranging your insurance quick, simple and easy.

 

Personal Details

  • Your personal details, including your full address, home, work and mobile phone numbers, and email address.
  • The full name, address, date of birth, duration of licence to drive, and 5-year claim and conviction record of the person who will be driving the vehicle(s).
  • Your membership number for the JEC
  • How many vehicles are in the household (you might qualify for multi-car insurance).

 

Vehicle Details

  • The make, model and year of the vehicle(s).
  • The current overall mileage of the vehicle(s).
  • The engine size and specification of the vehicle(s).
  • All modifications made to the vehicle(s), such as the installation of non-standard wheels, aftermarket electronic equipment, performance-enhancing parts, or cosmetic upgrades.
  • Any previous professional valuations of the vehicle(s).

 

Vehicle Use

  • Where the vehicle(s) is/are typically kept overnight (e.g. a garage).
  • The expected annual mileage of the vehicle(s).
  • What the vehicle(s) is/are typically used for.
  • What cover (if any) is required for:
    • Commuting or driving as part of a job.
    • JEC TrackSport, or other such situations.
    • Use of the vehicle(s) abroad.

Agreed values

We have a number of highly-qualified experts who can inspect your vehicle prior to purchase and provide you with a full written report. In addition to their complete understanding of the mechanical and aesthetic aspects of vehicle inspection, they have extensive experience with the Jaguar marque which perfectly equips them to identify the unique requirements of specific models and years, something that is particularly important for older cars.

The cost of an inspection begins at £100, with the final figure determined by the time needed and the distance the inspector is required to travel. We can guarantee that your inspection will be cheaper than an equivalent AA or RAC inspection.

This small upfront outlay could save you thousands in the long term.

To arrange an inspection simply call JEC Head Office on 0117 969 8186 and they will provide you with details of your nearest inspector.

Also from our club HQ in Bristol we can give you an official valuation for insurance purposes. Our valuations are accepted by all leading insurance brokers and Companies.

Simply call 0117 969 8186 for details

GETTING STARTED

Jaguar Enthusiasts’ Club Insurance is designed specifically for members of the JEC. That’s why it covers JEC TrackSport events and offers cover for JEC Young Enthusiasts. Furthermore, the scheme recognises that members may have a combination of newer and more historic Jaguars and so the scheme caters for all, other individually or part of a multi-vehicle offering.

Club insurance doesn’t operate the way standard insurance does. While it does still take a vehicle’s mechanical characteristics into account, it also places a lot of emphasis on how the vehicle is used, cared for and maintained.

Club insurance also offers a host of benefits and products that you simply cannot get outside of membership of the JEC, such as member to member cover for example. This enables you to drive your friends Jaguars at regional meets, events and on tours with fully comprehensive cover and without the need to complete more paperwork or ring up and incur costs for adding named drivers.

This way, you’ll be comfortable knowing that you have a policy that fits your vehicle and your usage needs perfectly.