No Synchros, No Mercy: The Interceptor GTX's Straight-Cut Dog Box

Jensen's reborn Interceptor GTX pairs a Roots-blown 6.8-liter V8 with fewer than 20 percent original GM parts and a rear-mounted sequential gearbox that has straight-cut teeth, dog engagement, and exactly zero patience for your heel-and-toe technique. This is what a track prototype is supposed to feel like.

By Elena Voss · September 8, 2026 · Cars

Jensen has been resurrected more times than a horror villain. Jensen Motors wound down in 1993, flickered back between 1998 and 2005, then again in 2007, then again in 2010. Since 2015 the rights have sat with Jensen International Automotive, which spent recent years doing a handsome restomod of the original Interceptor. Now they have unveiled the Interceptor GTX: a track-only prototype, 960 horsepower, and a gearbox with no synchromesh. Against all experience, this one is worth taking seriously.

Consider who is building it. David Duerden, the project's lead, is a former aeronautical engineer who founded Compotec and supplied carbon-fiber parts to Formula 1. Standing next to him is Jeff Qvale, son of Kjell Qvale, the Norwegian-American dealer who joined Jensen in 1970 and whose money funded the Jensen-Healey era. Qvale was there when his father's involvement ended in bankruptcy. This time his family's name is on the door from the start, which is either confidence or the best-documented superstition in the British car industry.

What they have produced, per launch reporting from carsfera and radical-mag in the first week of September, is a car whose specification sheet reads like a dare: a supercharged 6.8-liter GM V8 rebuilt until almost nothing original remains, a rear-mounted six-speed sequential with straight-cut dog gears, aluminium chassis and bodywork, and an adjustable wing worth 771 pounds of downforce. Roughly 80 percent of the exterior design will carry into the road cars that follow: an Interceptor GTR and, later, a GT. Both will be offered with a proper H-pattern manual. Jensen understands its audience.

A Corvette engine that is no longer a Corvette engine

Start with the heart, because Jensen did. LME in the United States is developing the 6.8-liter V8 from a GM small-block starting point, boosted by a Roots-type supercharger, and Jensen says fewer than 20 percent of the original components survive the overhaul. CNC-machined cylinder heads, titanium valves, a fully forged rotating assembly, and motorsport-grade everything else. MoTeC manages the whole affair, which is the industry standard way of saying this engine will never have an idle you could describe as civilized.

Output sits at 960 horsepower in current form, with Jensen suggesting the architecture could eventually reach around 1,200 metric horsepower and nearly 1,500 Nm of torque. Pause on that for a moment: an American pushrod-derived V8, bored and stroked to 6.8 liters, breathing through a positive-displacement blower, in a British sports car, managed by Australian engine software, with the road to 1,200 PS left deliberately open. Nothing about that sentence belongs to one country. This is how hypercars get built now, by people who shop globally for the best person to solve each problem.

There is an engineering argument buried under the theater. A Roots supercharger delivers boost as a function of crank speed, not exhaust energy, so throttle response is immediate in a way turbochargers cannot fake. On a 6.8-liter engine with a forged rotating assembly, you can run serious boost without the rotating mass tearing itself apart, and the titanium valvetrain buys back the reciprocating mass that a big-displacement head would otherwise waste fighting its own valves at high rpm. CNC-ported heads then make the cylinder filling match what the blower can shove in. Each choice loads the dice for the next one. It is a coherent package, not a shopping list.

Keeping fewer than 20 percent of the donor engine's parts is not a rebuild. It is a confession: the block was convenient, and everything else was wrong.

The gearbox: straight-cut, dog-engaged, and proud of it

Then comes the part this article is really about. Power reaches the rear wheels through a Samsonas Motorsport six-speed sequential, rear-mounted in transaxle layout, with straight-cut gears and dog engagement. A carbon-fiber prop shaft connects engine to transaxle. A Wavetrac differential decides what to do with the torque.

Start with the teeth, because the choice is deliberate and slightly mad. In a conventional road gearbox, gear teeth are cut helically: angled relative to the shaft axis. Helical teeth engage gradually, roll into mesh quietly, and that is why your car's gearbox does not announce itself. The angled teeth, however, generate axial thrust along the shaft with every bit of torque they transmit. That thrust must be absorbed by thrust bearings, which means energy that could have moved the car is instead spent pressing gears sideways into their housings. Straight-cut gears have teeth parallel to the shaft axis. No axial component, no wasted force, stronger in mesh. The price: each tooth enters and exits engagement as a discrete impact, which produces the famous straight-cut whine, audible from roughly the next county over.

Dog engagement is the second half of the madness. A synchromesh gearbox uses friction cones to match gear speeds before engagement, which is why you can shift a road car politely. A dog box discards the cones entirely. The gears carry large rectangular dogs with generous backlash; the shift lever slams a collar into them; the engine computer cuts ignition for a few milliseconds to unload the dogs while it happens. Done properly, an upshift takes less time than a blink and feels like being shoved by a friend. Done lazily, it sounds like a toolbox falling downstairs. There is no middle ground, which is exactly the point.

This is why the gearbox matters more than the horsepower figure. Anyone with money can make 960 horsepower in 2026; supercharger kits for American V8s are a mature commodity. Choosing a straight-cut dog box for a car that previews road cars is a statement about what kind of company Jensen intends to be. The GTR and GT that follow will get H-pattern manuals and automatics, sensibly. But the GTX exists to establish the engineering culture first, at the track, where the whine is music and the dogs are correct. I respect the order of operations.

Rear-mounted: putting the weight where the work is

Mounting the gearbox at the rear axle is not fashion. A front-engine car with a rear transaxle shifts a meaningful mass of driveline weight behind the seats, nudging the weight distribution toward the rear wheels that put the power down. Corvette's C8 went further and put the whole engine there; the GTX keeps the V8 up front but refuses to let the transmission add to the nose's burden. A carbon-fiber prop shaft connects the two, and the material choice matters for more than weight: carbon's torsional stiffness-to-mass ratio means the shaft can transmit torque with minimal twist while spinning at driveshaft speeds without the critical-speed drama of a long steel tube. The Wavetrac differential, a helical gear limited-slip with wave-cut side gears that maintain friction even when one axle is unloaded, keeps the whole assembly honest when a curb gets involved mid-corner.

None of this is new technology. Transaxles date back decades, and dog boxes are older than synchromesh. What is new is the deliberate pairing of every archaic choice with a modern excuse: the straight-cut gears are efficient, the dogs are faster than any dual-clutch for engagement feel, the transaxle layout needs no marketing department to justify. This car is an argument that the best parts of old racing engineering were never disproved, only muffled.

Aluminium bodywork, from a carbon-fiber man

Here is the detail I keep returning to. Both the chassis and the bodywork are aluminium. David Duerden made his name supplying carbon-fiber parts to Formula 1, and he chose to build this car out of aluminium. That deserves more than a passing nod, because aluminium bodywork is nearly extinct in 2026: carbon tubs dominate the hypercar world, and stamped steel dominates everything below it. Forming and finishing aluminium panels by hand is slow, expensive, and unforgiving of mistakes. Nobody does it as a cost play.

So why? Partly heritage: the 1966 Interceptor wore its Touring-designed body as the car's defining asset, and an aluminium resurrection carries that lineage better than a carbon tub ever could. Partly repairability and low-volume sanity: a small manufacturer can work aluminium with tools and people rather than autoclaves and prepreg supply chains. And partly, I suspect, contrarian instinct. When everyone in the hypercar business is printing titanium nodes and weaving carbon monocoques, building a hand-formed aluminium body is the most radical material choice available. It just happens to be 60 years old.

Aero, brakes, and the numbers that exist

The chassis hardware is the expected motorsport catalog, executed without visible corner-cutting: double-wishbone suspension with three-way adjustable Nitron dampers, custom 20-inch forged aluminium wheels, and serious brakes. One note of honesty here: carsfera credits AP Racing with the braking hardware while radical-mag names BG Developments for the braking system. The two may not contradict each other (British motorsport suppliers mix and match), but the car is a prototype and the spec will evolve. Treat the badge with caution until Jensen publishes a final sheet.

Aerodynamics get one clean number: the adjustable rear wing, front splitter, and flat floor combine for up to 771 pounds of downforce. That is a serious figure for a car with no published weight, and it is the only performance-adjacent number Jensen has put forward. No 0-60 claim, no top speed, no Nürburgring ambition yet. For a debut built around a 960-horsepower prototype, the restraint on the numbers is either admirable discipline or the first crack in the plan. Time will tell.

A history lesson, briefly, because it matters

The original Interceptor matters here because its whole identity was American muscle in a British suit. Launched in 1966 with bodywork by Touring of Milan and power from Chrysler V8s, it was a grand tourer for people who wanted a 383-cubic-inch answer to every question. Its stablemate, the Jensen FF, was the first production car with four-wheel drive and the first with ABS, a genuine technological landmark that arrived years before anyone else worked out the marketing. Jensen's history is not one of restraint; it is one of ambition exceeding the company's ability to survive its own products.

Which is precisely why the GTX's road-car follow-ups are the real test. Jensen says the performance-focused GTR arrives as early as next year, at least as powerful as the GTX but road-legal, with the more luxurious GT after that. Roughly 80 percent of the GTX's exterior design carries over. The interior, currently a race car with an FIA cage, Tillett carbon seats, six-point harnesses, and a MoTeC display, gets Alcantara and orange stitching as a peace offering. If the road cars keep the aluminium bodywork, the manual option, and the supercharged V8's character, Jensen has a genuine product. If they arrive as softened design exercises, the GTX was theater.

What we don't know yet

Honesty requires the caveats, and this car has more than most. No weight has been published, which makes the 771-pound downforce figure impossible to contextualize. No acceleration or top-speed figures. No lap times, no Nürburgring plans, though Lukas Czinger's recent comments about American hypercars chasing the AMG One's record suggest the Green Hell has become the industry's mandatory pilgrimage and Jensen will be watched for signs of booking time. I have not driven it, and almost nobody outside Jensen has driven it at all.

Worth asking: does a straight-cut dog box make any sense in the GTR road car, or does the GTX's gearbox exist purely as culture-setting? How does a 6.8-liter Roots-blown V8 with MoTeC management behave at idle in traffic, and does it matter? Can a small British manufacturer service a bespoke transaxle, a supercharger, and aluminium bodywork through any dealer network, or does every owner need a relationship with the factory? And the big one: Jensen has died four times. What, structurally, is different this time?

None of those questions diminish what debuted this month. A reborn British marque took an American V8, kept almost none of it, bolted a blower on top, hung a motorsport gearbox off the back with no synchros and straight-cut teeth, wrapped it all in hand-formed aluminium, and pointed it at the track before the road. The 960 horsepower is the headline, but the gearbox is the story. No synchros, no mercy, and about time.