The Glasshouse GT: History of the Jensen Interceptor

In the pantheon of British grand tourers, few cars possess the unique blend of brutal American muscle and sophisticated Italian styling quite like the Jensen Interceptor. Born from the ashes of the 1960s and produced during the turbulent economic climate of the 1970s, the Interceptor remains a striking anomaly in automotive history. It was a car that defied categorization: a heavy, hand-built British coupe powered by a massive Chrysler V8 engine, cloaked in a body designed by an Italian coachbuilder, and built in a factory in the West Midlands.

This is the factual history of the Jensen Interceptor, tracing its evolution from the drawing boards of Carrozzeria Touring to its modern-day resurrection.

The Genesis: From CV8 to Interceptor (1966–1969)

By the mid-1960s, Jensen Motors, a family-owned manufacturer based in West Bromwich, was known for producing niche, low-volume vehicles. Their previous model, the CV8, was a successful grand tourer, but by 1966, the company’s directors, brothers Alan and Richard Jensen, recognized the need for a successor. The goal was to create a more refined, aerodynamic, and spacious GT car that could compete with the likes of the Jaguar E-Type, albeit with a different philosophy.

Jensen had established a strong relationship with Chrysler, which supplied the V8 engines for their cars. To design the new body, Jensen turned to the renowned Italian design house Carrozzeria Touring of Milan, famous for their work on the Alfa Romeo Disco Volante and the Ferrari 250 GT SWB. Touring utilized their patented “Superleggera” (super light) construction method, which involved an aluminum skin over a tubular frame.

The result was the Jensen Interceptor, unveiled at the London Motor Show in October 1966. The design was breathtaking: a long, low-slung nose, a distinctive double-bubble roof (a signature Touring element to accommodate headroom without increasing the overall profile), and a vast glass area that earned it the nickname “The Glasshouse.”

Production began in 1967. The early cars, now referred to by enthusiasts as Mark I Interceptors, were powered by the Chrysler 383 cubic inch (6.3-liter) V8 engine. This was a time when British sports cars typically relied on small-displacement, high-revving four- or six-cylinder engines. The Interceptor, however, offered 325 brake horsepower and a top speed of over 130 mph, placing it in a different performance league entirely.

The Mark I featured a distinctive interior with wood veneer dashboards, bucket seats, and a center console housing the Jaeger instruments. However, the early cars were not without faults. The complex Touring body was expensive to produce, and the aluminum skin was prone to oil canning (denting). Furthermore, the car was heavy, weighing nearly 3,000 lbs, which put a strain on the braking system.

The Westbury Era: Mark II and the Introduction of the FF (1970–1971)

In 1970, production of the Interceptor underwent a significant change. Due to financial pressures and the complexities of Italian coachbuilding, Jensen decided to bring the bodywork production in-house. The new bodies were fabricated at the Jensen-owned Westbury plant in Wiltshire, utilizing the original Touring dies but with subtle modifications.

This ushered in the Interceptor Mark II. The most noticeable visual change was the replacement of the rear hatch glass. The Mark I featured a complex, curved glass hatch that was incredibly expensive to manufacture and prone to stress fractures. The Mark II replaced this with a flat, rectangular glass panel set into a steel frame, which was cheaper to produce and more practical.

While the exterior remained largely similar, the Mark II is historically significant for one major innovation: the introduction of the Jensen FF (Ferguson Formula) in 1967, which continued through this era. The FF was the first non-all-wheel-drive production car to feature a Ferguson-developed all-wheel-drive system, coupled with a Dunlop Maxaret anti-lock braking system—a technology previously reserved for aircraft.

The FF was essentially a four-seat Interceptor (though the rear seats were very small) with a longer wheelbase to accommodate the drive shaft to the front wheels. It was powered by a 6.3-liter V8, and later a 440 cu in (7.2-liter) engine. Only 320 FFs were ever built, making them the rarest and most technologically advanced versions of the Interceptor lineage.

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The Peak of Power: Mark III (1971–1976)

The definitive and most recognizable version of the Interceptor arrived in late 1971: the Mark III. This model represented a major overhaul, intended to modernize the car and address the reliability issues of the earlier models.

Styling and Interior: The Mark III featured a completely redesigned rear end. The previous flat glass was replaced with a large, wrap-around curved glass window, giving the car a sleeker, more integrated look. The rear lights were changed to vertical units, and the front received a new fiberglass nose cone with integrated headlamps and indicators. Inside, the dashboard was redesigned with a full-width walnut veneer fascia, and the heating/ventilation system was significantly improved (a notorious weak point in the Mark II).

Mechanical Specifications: The Mark III launched with the 6.3-liter (383 cu in) V8, but in 1972, due to US emissions regulations, Jensen switched to the Chrysler 440 cu in (7.2-liter) V8. This engine produced 350 bhp in its initial form, making the Interceptor one of the fastest production cars in the world, capable of 0-60 mph in under 7 seconds.

Trim Levels and Models: Throughout the Mark III production run, Jensen offered several trim levels and body styles:

1. Standard Mark III: The base model, featuring the 440 V8, automatic transmission (TorqueFlite), power steering, and leather upholstery. It was a pure grand tourer.
2. The JPS (John Player Special) Edition: Introduced in 1972 to celebrate Jensen’s motorsport involvement (specifically the BMW 3.0 CSL “Batmobile” racing program). Limited to approximately 100 units, these cars were finished in unique black and gold livery, matching the Formula One sponsorship colors. They featured gold trim, gold wire wheels, and a bespoke black leather interior.
3. The 440 Coupe and Convertible: While the coupe was the flagship, Jensen also produced a small number of convertibles. The convertible was structurally distinct, featuring a reinforced chassis to compensate for the lack of a roof. It was a heavy, luxurious open-top car, often criticized for its weight but admired for its presence.
4. The 6.3 Liter (Early Mark III): The very first Mark IIIs retained the 6.3-liter engine before the switch to the 440. These are rare and sought after for their simpler emissions equipment (pre-catalytic converters).

The Final Years: SP and The End of Production (1975–1976)

By the mid-1970s, the automotive landscape had changed drastically. The 1973 Oil Crisis sent fuel prices soaring, and the Interceptor, with its single-digit fuel economy, became an anachronism. Furthermore, stricter emissions regulations in the US (Jensen’s primary export market) strangled the performance of the large V8s.

Jensen attempted to keep the car alive with the introduction of the Interceptor Series 4 (S4) in 1974, but this was largely a facelift of the Mark III. The S4 featured a new fiberglass front end, revised rear lights, and a plastic grille. However, production numbers were low.

The final iteration was the Interceptor SP (Special Performance), produced in 1975 and 1976. The SP was an attempt to extract more power from the 440 V8 while meeting emissions standards. It featured a dual-exhaust system, a modified camshaft, and a higher compression ratio, yielding around 385 bhp. Visually, the SP was distinguished by its “power bulge” on the hood (necessary to clear the air cleaner) and often featured distinctive “spider” alloy wheels.

Despite the SP’s improvements, the writing was on the wall. The cost of building the Interceptor by hand—using expensive materials like leather, walnut, and aluminum—was no longer viable in a market shifting toward mass-produced, fuel-efficient vehicles. In 1976, after a production run of approximately 6,400 units (including the CV8 and FF), Jensen Motors ceased trading. The Interceptor was no more.

Technical Overview and Engineering

The Interceptor was a fascinating engineering hybrid. The chassis was a conventional steel box-section frame, but the body was a mix of steel (doors, roof) and aluminum (bonnet, rear quarters). This combination contributed to the car’s durability; many Interceptors survived the harsh British winters that destroyed other sports cars of the era.

The suspension was independent at the front with double wishbones and coil springs, and a live axle with leaf springs at the rear. This setup provided a comfortable ride suitable for long-distance cruising, though handling was often described as “grandiose” rather than razor-sharp. The power steering was essential, given the car’s weight and the narrow British country lanes.

The Interceptor in Culture

The Interceptor’s unique aesthetic made it a favorite of film and television producers. It appeared in various British crime dramas of the 1970s, often driven by villains or wealthy anti-heroes. Its menacing stance and American V8 rumble gave it an aura of danger and sophistication. In recent years, it has enjoyed a resurgence in popularity among collectors and has appeared in modern media, serving as a period-accurate prop for the 1970s setting.

The Modern Era: Revival and Future Outlook

For decades, the Interceptor remained a cult classic—admired but often overlooked in favor of more mainstream classics like the Jaguar E-Type or Porsche 911. However, the 21st century has seen a dramatic shift in its status.

In 2008, a new company, Jensen International Automotive (JIA), was formed. They acquired the rights to the Interceptor name and began producing “re-imagined” Interceptors. These modern vehicles utilize the original Touring design but are built on a modified chassis with modern technology. They are powered by a 6.1-liter Hemi V8 (the same engine found in the Dodge Charger) producing 425 bhp, coupled with modern disc brakes, air conditioning, and fuel injection. While purists debate the authenticity of these new builds, they have undeniably raised the profile of the original car.

In 2019, the rights were acquired by a new company simply named Jensen. They have announced plans to produce a limited run of 25 “Interceptor Series 5” cars. These are intended to be more faithful to the original, featuring the classic styling but with modern engineering tolerances and safety features.

Conclusion

The Jensen Interceptor was a car born out of passion and defiance. It defied the trends of the 1960s by embracing size and weight; it defied the trends of the 1970s by refusing to downsize its engine; and it defied convention by blending British craftsmanship with Italian style and American power.

Today, the Interceptor is recognized not just as a classic car, but as a piece of automotive art. It represents the final chapter of the British boutique coachbuilder—an era when cars were built by hand, with distinct personalities and flaws. As the automotive world pivots toward electrification and autonomy, the roar of the Interceptor’s V8 serves as a visceral reminder of a time when the journey was just as important as the destination. Whether in its original 1970s guise or a modern revival, the Interceptor remains a timeless symbol of the Grand Tourer.