Jaguar MkX/420G (1961 – 1970) Review

Jaguar MkX/420G (1961 – 1970) At A Glance


+Enormous, with room from three on the front bench seat alone. Still looks and feels like a Jaguar, despite how big it is.

-Complex to restore and low relative values make this often financially unviable, so look out for bodged examples being paraded as nice ones.

The arrival of the MkX hard on the heels of the E-type, meant that Jaguar's range was getting an all-new modern look for the 1960s. Out went the bulkiness of the old Mk7-Mk9, ushering in a sweeping style that - indirectly via the XJs - would live on into the 21st century.

In its day, the MkX was physically huge and easily capable of seating six full-sized adults. But appearances are deceptive, because the MkX was far more agile than its huge width and length implied, especially in 3.8-litre manual transmission form. All cars had power-assisted steering as standard and disc brakes all-round with
servo assistance.

The torquier 4.2-litre engine was introduced in 1964 making the MkX even more effortless if not any quicker; and then it became the 420G when the range was rationalised in 1966. A few limousines based on it were built, but the car lived on into the 1980s as it was used to underpin the iconic Daimler DS420 limousine, as beloved by royalty and lord mayors across Britain.

Ask Honest John

Do I need an E5 additive for my classic Daimler?

"I am fortunate to have and look after a 1969 Daimler Sovereign (420). I am having to use E5 fuel and would appreciate your guidance on which additive(s) would help protect the Jaguar XK engine? I believe lead replacement is less of an issue with this engine but I am concerned about the adverse effects of the ethanol content of E5 petrol."
All XK engines can run happily on unleaded fuel (with no additives) because their alloy heads had to be fitted with hardened valve seats. However Jaguar specified 5 star petrol because of the 9:1 compression ratio so I suggest you use Super Unleaded wherever possible - Shell V-Power, BP Ultimate or Total Excellium. It's a small price premium but given you are unlikely to be using the car as a daily driver it will be money well spent with no pinking and a more spirited performance
Answered by Alan Ross

My car has been SORN'd for several years - how do I get it registered and back on the road?

"My 1970 Jaguar 420G has been on a SORN for a number of years. The restoration is nearly complete. How do I get it registered and back on the road?"
Your Statutory Off-Road Notification will be cancelled when you tax your car online. To do this, you'll need to get it MoT'd (you're allowed to drive to a pre-booked MoT appointment if your car is on SORN) and it will also need to be insured.
Answered by Keith Moody
More Questions