JIA would like its revitalised Interceptor to be seen as an alternative to, say, a new Aston Martin. That makes no objective sense, but JIA just needs 12 to 18 people each year to whom the objective doesn’t matter.

Several worlds are colliding here. The surroundings are 1970s – airy cabin, angular dashboard, proprietary rather than bespoke switchgear, vintage-flavoured nascent modernity, a degree of dynamic disconnection – but the measurements are not. This is a Jensen Interceptor, a car we all thought somewhat large back then, but by today’s standards it’s almost compact. And they surely never barrelled along like this.

Over another crest on the A361, Northamptonshire, and yes! 
Enough straight for another overtake. Brush the accelerator, trigger an almost certainly unnecessary downshift because it can’t help itself, feel the tail squat and the nose rear up as the Jensen hurtles towards the next brow, exhaust pipes spitting V8 fury, self squeezed hard into seat. Where’s all that weight, all that inertia, now? And how long can it continue before the fuel gauge no longer acts as an accelerometer because there’s no fuel left to gauge?

Longer than it would have done back then, that’s for sure. Where 
once the hydrocarbon energy was dissipated within a Torqueflite 
torque converter (how apt a name) or remained untapped as all those hydrocarbons spewed out with much burning left undone, now it all reaches the wheels. More pace, less waste.

Some numbers. In 1972, a new Jensen Interceptor SP cost £6977, weighed 1780kg and averaged around 11mpg (that’s SP as in Six-Pack, carburettors and 7.2 litres.) In 2011, the Interceptor S you see here 
costs circa £107,000, weighs about 1530kg and averages maybe 20mpg. Not only that, it has 429bhp against 330, and slightly more torque despite giving away just over a litre of engine capacity.

That’s progress for you, all of it good apart from that price business. The Interceptor S even has an architecturally similar V8 engine with just two valves per cylinder, operated by antediluvian pushrods. However, the intervening four decades have brought us aluminium instead of cast iron for the block and heads, an ultra-modern fuel-injection system instead of three slurping Holley twin-chokes (or 
dual-throats or double-barrels, as their maker probably preferred), and a four-speed, aluminium-cased automatic gearbox with rather less slurring of its torque converter.

Also, the engine comes from a slightly different source. You could argue that this compromises notions of purity but little, because no Jensen ever had a Jensen engine. They were always ‘bought out’, 
from Chrysler if a V8, as fitted from the C-V8 right through to the end 
(I don’t include the shortlived, curiously styled and Ford-propelled 
S-V8 here). So it’s not too sacrilegious to knock on a different Detroit door and acquire a Chevrolet V8 instead, especially when that V8 is 
a Corvette-spec LS6 unit.

Ludicrous though it seems, this 6162cc motor is still what GM calls a ‘small-block’, even though in this capacity it is no longer small and there is no longer a big-block to establish relativity. No parts are shared with the 1955 progenitor of the breed, but the bore centres are the same and the line of descent perfect.
So what do we have here, exactly? This car, finished in what looks like metallic Morris Minor (it’s actually a Lamborghini colour), showcases the products of the latest of a string of companies to bear the Jensen name. Jensen International Automotive, or JIA, takes a salvageable Interceptor donor, strips it, then gives the bodyshell to Limn Historics of Twyford, Bucks, for metalwork replacement and modern-standard pre-paint treatment, painting and rustproofing.

The shell is also modified as necessary to the new Interceptor S specification, most obviously with a deeper front valance to improve looks and aerodynamics, the removal of some water traps, and new mountings to suit the other key modification, a Jaguar XJS-type rear suspension with outboard brake discs. So it’s goodbye to the heavy live axle and leaf springs, as well as the iron engine and transmission.

Back at the Banbury workshop, the incipient Interceptor S is (re-)assembled with half a turn removed from the front coil springs for a lower ride height (despite the lighter powertrain) and a stiffer spring rate to match that at the back. Spax dampers are used all-round, and the front brakes are enlarged AP Racing items. There’s a bit more castor, achieved by shimming the wishbones fore-and-aft, but the Adwest power steering rack is as fitted first time around. The cabin is fully retrimmed, of course.

Now, all this might bring on a degree of déjà vu. You’ll probably know that this is not the first time that rebuilt, Corvette-powered Interceptors have tempted those craving a classic-car fix underwritten (one hopes) with modern reliability. A firm called V Eight Ltd, owned by an entrepreneurial group which had already taken over Cropredy Bridge Garage (the Jensen restorer that had acquired pattern and production rights, plus stock, from the Jensen Parts and Service company that was itself salvaged from the original Jensen Motors), developed and marketed just such a car out of Cropredy Bridge. Unfortunately, V Eight ran out of money and the enterprise fizzled out.

Two good things have arisen from this. Cropredy Bridge’s original owner now runs the business again as it used to be run, and several people involved with V Eight have now formed JIA. The cars currently being completed at JIA are those left unfinished when V Eight folded, 
so worried customers will get their cars after all. Limn Historics is working on its first JIA shell, and it is the improved standards of 
these shells, and the greater cost to produce them, that is the chief reason for redesignating these next JIA cars as Interceptor R rather than Interceptor S.

Clear so far? This Morris Minor metallic Interceptor, then, is a V Eight-
made car but selected for our appraisal as closest to the quality promised in the future. Its panels fit tolerably well, for example, which wasn’t always the case before it was realised that doors, bonnet and that vast, glassy tailgate really need to be used on the shell to which they were fitted originally. Super-accurate mass-production items 
they were not. Other obvious external changes are meshed instead of finned grilles behind the front wheels, and 17in wheels in the style of 
the original 15in items. Tyre section is now a hefty 235/50. Under the bonnet, the installation looks factory-neat and there are even Jensen logos on the rocker covers.

Inside, it’s not quite so neat but, again, improvements are promised. There’s engine-turned aluminium on the centre console (your choice), while the straight-from-Corvette transmission selector and the italicised-script ‘start’ button jar a little. The instruments are by CA Industries, which bought out Smiths, and though superficially retro they look a touch too kit-car. Again, changes are planned. Original 
dials can’t be used because today’s triggers and sensors are electronic rather than mechanical. As for the original-type air-con controls, you’re either roasting or shivering.

Oh yes. This particular engine has a Corvette ‘performance pack’, consisting of a hotter camshaft and ECU recalibrations to suit. Its 480bhp explains this Interceptor’s explosive pace, made all the more dramatic by a pair of rather large-bore tailpipes. Hot cams often mean less torque at idle, which is why the Jensen sometimes stalls as Drive is selected. The answer is to squeeze the throttle just as the lever snicks into D, and enjoy the blast-off that ensues. ‘Yes, it’s rather less benign with this engine,’ says JIA’s technical guru David Duerden, ‘because that cam is a little bit wild.’

Then there’s that manic part-throttle kickdown, which can mean 
that without moving your foot the transmission will sometimes tire of, say, fourth (top) gear and its 33mph-per-1000rpm, and give you third, resulting in sudden unintended acceleration of a whole new sort. This is actually quite authentic, because the Jensen SP did something similar. The Motor road test describes how an increasing load on the engine, despite a steady accelerator position, could activate the four extra carburettor chokes, which relied on a drop in manifold vacuum to be opened. The result was a sudden surge of power, most amusingly at, say, a 110mph cruise when a slight uphill gradient was encountered. 
It was enough to open those chokes and the SP would then hurtle on to 130mph with no action from the right foot.

Marketing head Steve Bannister reckons his new Interceptor will reach 160mph and, judging by the gearing and the high-revs potency, he could be right. He also reckons it will reach 60mph in under 4.5sec, which is a claim compatible with the slightly lighter Corvette’s 4.3sec to 62mph. It certainly beats the old SP’s 7.6sec and 140mph.

Driving this Interceptor in busy, open-road, modern traffic is great fun because no-one expects it to take off as it does. But can it cope with corners and bumps? This much urge with original Interceptor underpinnings would be quite a liability, but the JIA car manages to contain the forces up to a point. The brakes are powerful but feel mushy in the test car, the steering has more feel than you’d expect (thank the extra castor for that) but it’s loose around the centre.

Get past that, and this becomes a surprisingly wieldy projectile, with controllable oversteer on tap whenever you want it. The Jaguar rear suspension gives good traction, untroubled by bumps in bends, and up to a point (that phrase again) this Interceptor feels quite tidy. That point is passed if you really get going on a bumpy, twisty backroad, upon which the dampers cry ‘enough’ and all becomes unsettlingly floaty. 
It doesn’t get out of hand though; all it’s doing is reminding you that, for all the honing beneath, this is still a 1970s Interceptor.

Onlookers love it for that. They will point, stare, admire, engage you in conversation. Other drivers enjoy its presence, too; there’s none of the envy or aggression you might encounter in something similarly quick but modern. And that’s very refreshing.

JIA would like its revitalised Interceptor to be seen as an alternative to, say, a new Aston Martin. That makes no objective sense, but JIA 
just needs 12 to 18 people each year to whom the objective doesn’t matter. Of course the price is ludicrous when you can buy a very tidy, original Interceptor for around £15,000 (leaving you plenty of spare funds for the extra petrol), but then it’s always much more expensive 
to restore a car properly than the car ever cost to build in the first place. All we need, then, is to be sure that JIA’s next ‘R’ cars really are built 
to the promised impeccable quality, and for proof of that we’ll have to wait a couple more months.

Already, though, JIA has had much interest from potential customers. Which just proves that with Octane-flavoured cars, logic never figures very highly