Jaguar does not build many cars like the Jaguar Mark IX with 3781 cc DOHC I-6, built from 1958 to 1961 at the height of the post-war boom.
The background
The Jaguar Mark IX is a four-door luxury saloon car announced 8 October 1958 and produced by Jaguar Cars between 1958 and 1961. It was generally similar to the Mark VIII it replaced, but had a larger, more powerful 3.8 litre engine, 4-wheel disc brakes, and power assisted recirculating ball steering among its mechanical improvements.
Visually the early versions were identical in exterior appearance to the Mark VIII except for the addition of a chrome "Mk IX" badge to the boot lid. Later versions had a larger tail-lamp assembly with an amber section for traffic indication, visually similar to the tail-lights of the smaller Jaguar Mark 2. It was replaced by the lower and more contemporary-styled Mark X in 1961.
The engineering
Under the skin sits 3781 cc DOHC I-6. Kerb weight is 4000 lb. The wheelbase is 120 in. These are manufacturer figures carried by Wikipedia and Wikidata, not road-test measurements.
Where it sits
Where it sits in Jaguar's history is not in doubt: the Jaguar Mark VIII came before it; the Jaguar Mark X followed it; it was built at Coventry, England, United Kingdom. On a showroom list of its day it stood against the Mini Mini, the Nissan Patrol, the Dodge Challenger. Its Jaguar stablemates include the F-Type and the Vanden Plas.
The money
There is no federal ownership record for the Jaguar Mark IX — it predates the complaint database or was never sold in the United States — so MotorJury publishes no running-cost figure for it. For a car of this age the price is set by the collector market and the condition of the individual example, not by a formula.