Because cars like the Lightweight GT (G.T. in Aston-speak) were more than fast enough to be exciting - certainly when racing on skinny period rubber - and accurate enough to enable the best drivers to drive them impressively hard. They were also much more closely related to their road-going sisters that anything that followed, with even the more modestly talented able to have a serious go at thrashing one. Skill was necessary to get the best out of them; top-flight drivers piloted cars like the GT alongside faster formulae. But this generation of sportscars was also well suited to the sort of well-nourished gentleman amateurs who would be too unfit to get close to elite motorsport within a few years.
Plus which, did a more gorgeous car ever go racing?
Aston announced its plans to build 25 'Continuation' DB4 GTs in late 2016, with the official justification being that, between 1959 and 1963, it only built 75 of the original GTs, against the official homologation requirement of 100 to justify the car's racing career. By choosing to make the balance, and to charge a £1.5m pricetag before taxes, the project had enough budget to both make money, and to allow Aston's in-house restoration division, Aston Martin Works, to do a properly proper job.
Yet Paul Spires, Works' Commercial Director, admits that committing to build so many cars was still a leap into the unknown. Potential buyers had been sounded out, but the production numbers are a huge increase on the six 'Continuation' Lightweight E-Types that Jaguar did. "We could have had people back out or get cold feet," Spires says, "but there were no problems. Our main concern was selling the cars to buyers who would get them seen around the world."
That's why just three of the finished cars are destined to remain in the UK, and even the U.S. is only set to get five, with that number including the very first, the prototype that I have been invited to a gloomy Silverstone to have a go in. Its new owner is set to take delivery in just a couple of weeks, with the last-minute list of jobs including replacing the vinyl over-body stripes with period-appropriate hand-painted ones. But I'm under strict instructions not to add any extra patina through Silverstone's barriers or gravel traps.
We'll get to the business of what it's like to drive somebody else's seven-figure classic sportscar on a damp, slippery racetrack soon. But first, the sheer wonder of meeting the thing up close. The new lightweight GT is a lovingly produced facsimile of its famous predecessor, with the research involving both scanning originals and poring over the 450 engineering blueprints that Aston still has in the archive. Yet it's obvious that it has been built to a far higher standard, with tight panel gaps and a paint finish good enough up close to make the finished GT look like one of those freakishly perfect video game renderings brought to life.
What the DB4 GT definitely isn't one of those "made better" restomods; there's no power steering or fuel injection here. Changes have been made around improving safety, and allowing the GT to race in the historic series that will have it - there's a full roll cage, motorsport-grade bucket seats and harnesses and plus fire extinguisher and electrical cut-out switches integrated into the front wing and dashboard. Under the surface the aluminium fuel tank also contains an FIA-grade safety bag.
Beyond that, everything else is as original as possible. The steel chassis has been built to almost exactly the same specification as the original (it turns out that all the original GT chassis were made with a very slight kink, which has been corrected). Chassis and the six-cylinder engine are manufactured by suppliers, but assembly, trimming and painting has all been carried out by Works in Newport Pagnell, making the DB4 the first car produced there since the first-generation Vanquish retired. External bodywork is hand formed from aluminium just 1.2mm thick. "It's very difficult stuff to work with," Spires says, "I had people begging to use thicker gauge stuff, which would have made minimal weight difference, but it wouldn't have been true to the original." In total, Works employees have spent around 4,500 hours on each car. Suddenly that pricetag doesn't seem quite so high.
But the GT is more than just a pretty face. It's been designed for life on track, both as a historic racer, but also through a track experience programme that Aston has offered owners alongside the car. While the prototype wears number plates and has indeed been road registered, the others are being sold - officially at least - as circuit-only. As such it's had to pass the same durability standards that Aston subjects its other racers to, including a 2,500-mile test at Nardo last year.
A few laps of Silverstone in January pose less of a challenge in terms of chassis loadings, although the risk of becoming infamous as the Bloke Who Got It Wrong is a real one. It's not actually raining as my track time approaches, but it has been for most of the morning and the track is slick and greasy, air temperature a bracing six degrees. Apparently Aston has made the National Circuit's first booking of 2018 and the surface is as green as St. Patricks Day at Shrek's house. Simon Dickinson, one of Aston's performance driving instructors, is on hand to both show the ropes and administer warnings. His first words strike a suitably cautionary note: "I can't tell you just how slippery it is out there."
Dickinson proves the truth of his assertion with a couple of demo laps and some beautifully held tail slides. Then we're back in the pits and, after warning me of the need to be aggressive with the dog ring gearbox, Dickinson heads off in search of somewhere warmer and it's my chance to turn back the clock.
Apart from the need to squeeze around the non-period roll-cage, and click into the intimate embrace of a six-point harness, the view from the driver's seat is more road than race with a beautiful wood and metal steering wheel and a plethora of chrome-bezeled instruments with all except the big rev counter soon forgotten. The straight-six engine fires into a lumpy idle, snorting through its triple carburettors. The shift for the four-speed gearbox is heavy, but first is where it should be and the clutch bites progressively enough for me to get rolling without the indignity of stalling in the pits.
Dickinson wasn't exaggerating about the lack of grip on the skinny Dunlops. The engine is tractable and pulls cleanly, but well before the throttle pedal is half way down I feel the adrenaline spiking sensation of the rear running short on grip; this on the run to Maggotts. The long right-hand sweep at Becketts knocks me down another couple of pegs, with what feels like a very conservative entry speed resulting in ungainly understeer. I wind off some lock and slow until the front end bites, but then a gentle but evidently over-keen throttle application starts the back sliding. I'm definitely not channelling Stirling Moss.
Yet even in the face of my cack-handedness, there's still a fundamental friendliness to the chassis in evidence. The brake pedal delivers impressively strong retardation when compared to the lack of lateral grip, and stays firm enough to allow the heel-and-toe throttle blip necessary to (almost) match engine and road speeds for the synchro-free gearbox; by the end of three laps I've pretty much got the hang of it. Finding some drier patches on the straights gives the chance to experience some more of the engine's claimed 340hp peak, with some impressive urge as the tacho needle gets closer to the red line. The Continuation is brawnier than the original thanks to a bigger capacity 4.1-litre engine; but even with the lesser 3.7-litre unit the period GT was one of the fastest cars in world when it was new.
I certainly don't get close to mastering it during my short stint. But by the time I return to the pits I can at least see the technique to aim for in low-grip conditions: trust the brakes to slow right down, turn in very carefully and then use the throttle to help get the back involved and the car turning, but without allowing it to get away. That's a fine line in wet conditions; small wonder so many of the photographs of this era's sportscars show them in four wheel drifts. For the elite drivers who piloted them, cars like the GT must have been dynamic blank canvases.
So is the Continuation a 'proper' GT? Given the fineness of the line that separates restoration from improvement in historic motorsport, that might well be a moot point - but it's still interesting to see what the market thinks. You might expect that increasing the total number of DB4 GTs by a third would reduce the value of the existing cars, or at least slow the rate at which they were climbing. Yet that hasn't been the case, with period GTs rising even more substantially since Aston announced the Continuation project, and to the point where - to judge from the infrequent public sales - you would need to spend twice as much to get an original GT in non-lightweight spec.
The good news is that the project seems to have given Aston a taste for such adventures. While there are no official plans for another reanimation project yet, Paul Spires admits that the appetite is definitely present: "having put together such an exceptional team, and created such an exceptional car, it would be a shame if they weren't allowed to do something else."
Get your nominations for what Aston should do next in below.
SPECIFICATION - ASTON MARTIN DB4 GT 'CONTINUATION'
Engine: 4,211cc, six-cylinder
Transmission: 4-speed manual, rear-wheel drive
Power (hp): 345@6,000rpm
Torque (lb ft): TBC
Top speed: TBC
Price: £1.5million (plus taxes)