1959 Jaguar XK 150 SE 3.8-Liter Coupe

This car, Lot 349, sold for $134,045 (£109,250), including buyer’s commission, at Bonhams’ Goodwood Festival of Speed auction on June 24, 2022.

Most people know me as an Alfa or Aston guy, but the reality is that it was an XK 150 that started me down the path to where I am today. When I was about 15, my father abandoned his Dodge and bought a bright red XK 150 coupe. In Waterloo, IA, circa 1960, it was about the coolest, sexiest thing I had ever encountered. It hooked me into a lifetime of sports cars and racing.

It has been a while, though, so I am indebted to Chris Keith-Lucas of CKL Developments in the U.K. for bringing me up to speed. He is both the guru of 6-cylinder racing Jaguars and intimately acquainted with our subject car.

A race car?

In-period, nobody would have thought of racing an XK 150, at least not in the U.S. It was the softer, cushier “businessman’s express,” compared with the raw, hairy XK 120 and 140 roadsters that ran in the SCCA D Production class. Perspective changes with time though, and the 150 coupe has emerged as the better vintage racer.

In the early post-war years, Jaguar had developed a brand-new 6-cylinder engine to anchor its new line of cars. It was a cool piece of high-performance machinery, with a twin-cam, hemispherical head, almost a copy of the late pre-war Alfa Romeo 6C 2500 engine. Jaguar wanted to make a splashy introduction, so it created a concept sports car called the XK (for the engine) 120 (for how fast it would go). It was an immediate, insane success. Jaguar, which had intended to be a manufacturer of high-performance sedans, suddenly found itself in the sports-car business.

What resulted was the XK 120/140/150 series of cars that were produced from 1948 through 1961. These are all basically the same car: ladder frame, live axle on elliptical leaf springs, torsion-bar front suspension, and a 6-cylinder engine displacing 3.4 liters.

The wheelbase never changed, but the XK 120 had the engine set rearward for better weight distribution, which made fitting inside one difficult if your inseam is over 29 inches. The XK 140 moved the engine forward four inches, making the cockpit work for taller drivers. With the XK 150, the chassis was widened by two inches, and the coupe had its windshield moved forward three inches to make the interior roomier.

The classic look remained, particularly the bonnet. Jaguar literally took the production tooling for the 120/140 hood, cut it in half lengthwise, and stuck in a spacer to make the 150 version. Though the “OTS” (Open Two-Seater, in Jaguar-ese, i.e. the roadster) version could be a bit lighter, the racing weight for all of them was effectively the same: 2,750 pounds.

K Street

Racing preparation rules vary by organizer, and in the U.K., there are lots of options for vintage Jaguars. The most restrictive and universally accepted is the FIA Appendix K, and this is where the XK 150 has the advantage. All the models were built with 3.4-liter engines using two SU carburetors, but the late XK 150 S cars used a 3.8-liter engine with three SU carburetors, and the later “orange” straight-port head (effectively an early E-type engine). This means that any XK 150 can use the 3.8, and in racing trim it can be worth 40–50 horsepower more. The XK 150 also gets disc brakes vs. drums on the earlier cars.

This makes the XK 150 FHC (fixed-head coupe) the desirable racer of the bunch. The coupe bodywork stiffens the ladder chassis more than its weight hurts. Preparation is mostly a matter of removing the interior and the bumpers, putting in a fuel cell, a monster front anti-roll bar, and adjustable racing shocks. And, of course, building a serious engine. A good one makes about 310 hp, up from 250 for a stock 3.8 S.

The other advantage of the FIA rules is that the grid for these cars is strictly limited to 1961 and earlier. This means that, in terms of Jags, only the earliest E-types can compete. Keith-Lucas tells me that a well-driven XK 150 can run with them.

This brings us to how the car needs to be driven. With a chunk of cast iron up front and 6.00-16 tires, all Jags of the era will push like pigs if you let them. The racing technique is to turn in hard as early as you dare while you are still on the brakes. This will cause the rear to step out. Then you nail the throttle, correct, and keep the whole car sliding past the apex and out toward the next corner. An XK 150 is not for the timid.

It’s a classic driving style from the days of skinny tires and it is a ton of fun once you get into it. I am assured that the Jag’s handling when driven like this is progressive and easy to control. The engine has a wide torque curve, so steering with your right foot is rewarding.

Choose your weapon

These cars are best thought of as weapons, not collectibles. One of the caveats here is that our subject car is almost strictly a U.K. racing car. Over there you should be able to find an event filled with similar cars at least every month. In the U.S. you would be welcome anywhere but probably find yourself alone on the grid, which isn’t much fun.

The limited geographic appeal of our subject car also limits its value. American money has a serious impact on racing-car markets — even if most of the racing is in Europe — and it doesn’t chase these cars. Sales prices for racing Jags have also been down a bit over the past few years, but good cars remain strong. There is not a significant difference in values between racing and street-use cars, possibly because of the simplicity and reversibility of the racing mods.

I am told that this car was sold by a racer who wants to move up to an E-type and, similarly, bought by an E-type racer who wants to play with an XK 150. As all parties were knowledgeable and the car was known as a good example, this was a classic win-win, fairly bought and sold. ♦

(Introductory description courtesy of Bonhams.)