His face is a mask of genuine innocence, which says he's not waiting to have an existing prejudice challenged or confirmed. He really wants to know, and implicit in the question is whether someone who has driven one might know why they are worth five million pounds. Or is it dollars? As if it matters. As if a GTO might be some non-chemical, mind-expanding, sit-in drive-off turn-on experience which transports you to an area of tactile pleasure that only money can access. My answer is disappointing, formulaic, pisspoor. 'Yes, absolutely,' I say. 'There's a balance to it like nothing else. And twelve cylinders of course... I just love driving it.' He looks relieved nevertheless. It's not just a question of sensible investment then. It might still all be in the drive...

But although I don't have a sensible answer, it always sets me thinking. Are they as good as... what? As the modern equivalent? In road test terms, no. Nothing like. The cockpit is cramped, the pedals offset, the seat doesn't adjust, it's noisy, the brakes are marginal. And yet I was being honest when I said that it has a balance like nothing else and I really do love driving it. In fact I'd take a GTO anytime in preference to a modern GT racer.

After today I think I would probably take Nigel Hulme's AC Cobra too, but for different reasons. This is 39PH, the very car that AC sent to Le Mans in 1963 because Henry Ford and Carroll Shelby asked them to. Sponsored by The Sunday Times, it was driven by Ninian Sanderson and Peter Bolton, and covered 4171 kilometres to finish seventh, which is probably better than Shelby expected. It had been his inspiration to marry the 4.7-litre iron Ford boat anchor to the flimsy ladder chassis of the AC Ace but he already knew the combination would be blown off about halfway down Les Hunaudieres. Short nose, flat screen, big bum. Not great for several miles flat-out down one of the longest straights in the sport. Nobody knew a fat lot about car aerodynamics then but Shelby knew enough and so did Ferrari because by 1963 canny old Enzo had already bullied the FIA into accepting that the 'O' for Omologato version of his short- wheelbase 250 was a catalogue option. Now, let me see... I'll take the long nose and the long tail with its aerodynamic flip-up, that and the extra carbs on the 3-litre V12 engine. Oh all right, and I'll have the five speed 'box too. Any chance of a speedo to keep me legal? Tell you what, put it in a cardboard box and leave it on the transmission tunnel. I'll find somewhere to put it...

Ferrari made 36 of them and Nick's was driven to third overall at the 1962 race by Belgian works Ferrari driver Jean Beurlys, and Leon Dernier. The following year Beurlys - partnered by one Gerhard Langlois van Ophem - went one better with second overall, five places ahead of the Cobra. Nowadays that might have meant a media tour, journalist drives, manufacturer branding, etc, but then it was just another job for a car engineered by Ferrari for which they would happily take a cheque from anyone.

The Cobra - which Henry the Oval had funded to take on GM's Corvette back home - was possibly bigger news because it meant the Americans were showing an interest in Europe. Nearly 40 years down the road it's a different story and the Cobra enjoys a rather lower profile than the GTO. Nigel reckons his is worth about ΂£400,000 - more than they usually are because of its history and because it hasn't been modified and tarted up. Cobra lovers wouldn't hear anything of the kind, but hybrids - especially those with iron American engines - never quite make it into the same bracket as Ferraris, Maseratis, or Lamborghinis.

That iron V8 had been designed for a Canadian pick-up truck (but ended up in the Mustang and Thunderbird), displaces 4727cc and operates its two valves per cylinder via pushrods from a single cam buried in the vee. The road cars had a big single carburettor but the racers boasted a set of four twin-choke downdraught Italian Weber carbs and pushed out about 380bhp at 6000rpm. It was simple and strong and made up what it lacked in technical sophistication with the fortitude of iron and extra cubic inches. That helped it to pull from way down low in the range to overcome the limitations of a four speed 'box, and provided you didn't hang too many revs on it, the Ford would be as strong after 24 hours as it was at the start.

The Ferrari's 2953cc engine is all aluminium with iron cylinder liners, and each head has a single camshaft, driven by chains and gears. Six twin-choke Webers feed the fuel and it develops 290bhp at about 8000rpm. It thrashes and clatters mightily but there is no evidence to prove it was any less tough over a race distance than the Ford, although there's no doubt it is more highly strung, fluffs the odd plug and goes out of tune more easily. But apart from the difference under the bonnet and the aesthetics, which are in the eye of the beholder, the basic layout of the pair isn't that much different; both are aluminium-bodied, front-engined and rear-drive on a simple ladder chassis with double wishbones at the front and disc brakes all round. The Cobra has independent suspension at the back with more double wishbones and a Salisbury diff from a Jaguar, whereas the GTO has a big axle hung on cart springs like a Mk2 Escort, but makes up for that with coils at the front.

The Cobra has leaf springs at both ends, mounted across the car and pinned in the middle so that each half of the spring does one side, which is really vintage. Both cockpits are designed for small-ish people, the instrumentation is of the time - which is to say minimal, as are creature comforts in general - and both are noisy, physical and give me cramp in the legs. I wouldn't want them any other way.

Driving them
Or the bit that matters... Both of these cars are regularly driven on the road, which means they have silencers, lights and wipers and they don't overheat, but it's fair to say you probably wouldn't choose either to do a long journey. They are quite stiffly sprung and the vintage, tall-profile, square-edged Dunlop CR65 racers (Avons on the Cobra today) tend to follow ridges in the dry and their own agenda in the wet. Many's the time when I've thought there was oil on the track or I had four punctures only to find everybody having similar problems. A set of modern low-profile tyres would add a whole lot of grip, wet or dry, but if you want to race, tall profile is what the FIA says.

Besides, low wouldn't look right. So the racetrack is where they feel at home and we were lucky to have Goodwood because the place is much as it would have been in 1962. Some of the cambers have altered where the road has sagged over time, but there is only the one chicane and that was there then. The rest is very, very fast and it's definitely one of the places where you take a lap or two to decide just how much speed to take with you...

The GTO's seat still has its original leather covering, cracked with age and the slither of distinguished buttockry, and it's still a non-adjustable, vestigial bucket which does little to hold you no matter how tight the harness -which wouldn't even have been there in '62. Legs splayed to clear the splintery wooden rim, feet meeting the edge rather than the whole pedal, I always wonder how the hell I'm going to last an hour. Then I always forget about it. The hand falls straight from the rim to a gearknob level with your shoulders, ignition-on sends a whole set of needles flickering, then push the key to start. Twelve small cylinders seem to whirr over compression at double speed, then eventually it catches. Lazily at first as it clears out the fuel, then swelling to a multi-layered tenor like a windy church organ. A final tug of the belts which pulls the lap strap closer to your ribs, hook the big aluminium gearknob to the left, pull down against sticky synchro until you feel the clack in the metal gate, then ride the sharp, juddery clutch against a good stack of revs.

At first, the Ferrari will feel awkward and unco-operative. You follow each gearshift through the slotted gate and against those rubbery synchronisers and the time taken lets the revs die, then there's a real learner's jerk as the road speed hooks them up again. You brake, rock a foot uncomfortably in search of the accelerator, catch it and send the revs too high for the downshift, get the gear home too close to the corner, then ease a wheel which points the nose but does it with no real enthusiasm. And each corner you find you're in the wrong gear. Either the engine is limp and off cam, or the big rev- counter is edging towards our self-imposed limit of 7500 and calling for a shift mid-bend. It will go more - max power is at eight - but you do as you are asked. Start to get a bit more confident and push on a bit and the nose stops its pointing and washes away from the apex, then the tail starts to slither on the exit.

The soundtrack is wonderful, no doubt about that, and yet it doesn't feel like the magic tool of folklore, but I know from experience that this is because of your natural inhibitions. It is somebody else's multi-million-pound motor after all, and once on song it revs up so quickly, you can have the tell-tale at nine without even trying. So you have to put all that out of your mind and treat the GTO like any other racer. Nobody over-revs or falls off deliberately, so why should it be any different now... Up towards Madgwick, the double apex at the end of the pit straight with the sagging bit in the middle, into fourth and let it run to seven-five. Brake as the road starts to bend to the right but leave some extra momentum. Your previous experience says the car will just understeer, that there isn't enough grip at the front and you'll simply fall down into the dip. Trust me... Use the last touch of imbalance from the brakes and the tiniest easing of the wheel to start the turn, then the instant you feel a lean towards that front left tyre, you squeeze the power. Not right to the floor, but about half. This is the critical period. You want to cancel the push from the front but you don't want to sling the tail. Whoah... just a touch of opposite lock... but keep your commitment, don't lift off and with a bit of luck you'll find the car is neutral - or almost. You have to fidget a touch from now on, five degrees, maybe ten to the left, five to the right and back. The engine is on the cam and pulling as the car yaws maybe ten degrees, sometimes a bit more, but it's not an opposite-lock slide of the Meaden variety. It's a drift and you balance it with the power liberated by extra revs against steering which has become pin-sharp - as if it has magically acquired power assistance. Except that no powered helm could be this talkative. Each tiny shift in the yaw comes back to your fingertips as variation in weight. Each ridge in the road sends a kick to the rim.

It's all a bit like getting up on water skis, or getting a juggling trick going, or keeping upright on your first bike ride - it's all about how you begin and it simply doesn't work in a modern car, mainly because of the tyres. The modern variety is designed to grip rather than slide and will overheat very quickly if you do. Added to which there isn't the balance in the chassis that comes from a lightweight 300 horsepower engine in the front driving the rear wheels of a car weighing just over 1000kg. It's a combination the Ferrari had by birth and you can even lose it if you stiffen up the front springs and make it more like a modern car, which is what some people do. You can brake later, sure, and turn in harder, but then the tail slides until eventually you have to come back off the power.

At the same time as you learn how to use the other controls, your lack of inhibition means you have relaxed the biceps and slackened the grip on the aluminium knob. Now you just aim and flick, and the gate guides the lever perfectly while the synchros offer no resistance. The shift is swift, the ratios close, the organ chord shifts effortlessly down the keyboard. Each lap you think you can make everything sing with more harmony, dance with a daintier foot. You have discovered the magic. How could the Cobra follow a performance like this...?

It starts by offering better accommodation. The seat is similarly minimal, equally cracked and leathery, but it slides back and the wheel is clear of my thighs. Against that, the gearlever poking vertically from the tunnel needs thought rather than instinct. Then the engine spins more slowly on the starter, catches with similar indifference, then bellows and rumbles, sending a thrum through the frame. Picks up mighty smartly though - the slightest touch of the pedal flicks the needle round the dial and rocks the whole car - but the real difference is the way it sends the Cobra down the road. The V8 feels half as muscular again, pulls like a glider winch from nothing and pins you to your seat whatever the gear. There's that instant and massive response only found in genuinely powerful cars, where you add a bit more boot and the car always leaps forward as if there's a giant outside force sweeping it along. We did the sums later and found the Cobra was pulling 151mph at the end of the back straight but the way the pile of railway sleepers ahead starts to fill that flat screen leaves you in no doubt of the energy involved, just as it does when you approach St Mary's. Meanwhile the sheer V8 grunt and off-beat rattle soon becomes as addictive as the Ferrari's wailing V12. The grunt gives you other options, while at the same time creating its own problems.

The Cobra feels heavier at the front than the GTO and the steering is weightier, with lots of kickback. You have to wind up what feels like ten degrees of spring-loaded slack to overcome the initial push and make the nose point, then having succeeded, it will promptly unwind and push again. These are only small movements mind, much like the fidget in the Ferrari, but without the drift and I couldn't seem to get one of those going. There was never the sharpness that eventually came to the GTO's helm and never the calm that descended once you got the yaw started. But there were the other options. You don't need to take so much speed into the corner and keep the Cobra's engine on the cam, because it always is and you don't need to grapple a slower gearshift anything like as often. You can leave it in the higher ratio and use the vast well of torque to accelerate through the corner in the traditional slow-in, fast-out sense - added to which you just drive the car according to what it's telling you rather than having to apply a technique which feels alien at first. It's more physical but generally easier to access. That said, you do have to be careful.

Backing off the power suddenly in a corner had to be avoided at all times because it gave you the kind of oversteer you get from yanking on the handbrake. Then towards the end of my second stint I had found a good balance in the first part of Lavant - the double-apex sequence which leads onto the back straight - and while it wasn't quite drifting, the Cobra was driving hard, just on the point of oversteer when, suddenly, the rear end did a mighty jig, almost as if something had broken. The revs soared and the tail snapped to the left and although I caught it, it was a messy flop back the other way. Worst of all I had to lift... and it was such a good lap. It was either the leaf spring on the left had run out of up travel and sent the rate soaring, or the one on the right had run out of down travel and picked the inside wheel from the ground. Maybe both, but it happened all the more quickly in the face of that massive urge and it showed the limitations of transverse leaf springs.

But the Cobra was by no means the GTO's poor relation on the track. It didn't have the Ferrari's romantic side but in many ways it was probably a more effective racer for short dirty dogfights. Sure, when you have a clear track with long fast corners, you can use the Ferrari's balance to keep up the momentum, and where you have several miles flat out, like at Le Mans, the GTO's more beautiful body shape would count. But on a crowded track where you trip over slower cars and lose that corner entry speed, or somewhere with lots of slow corners, the Cobra's power would always come to the rescue. There was always more than the chassis could handle, so lose a bit to a mistake or have to lift because of traffic and you'd get it back with a prod of the boot. Former Ferrari world champion John Surtees (crotchety old cove that he is) recently admitted that he sometimes refused to drive a GTO because he knew he would trip over people while trying to use the car's strengths and he didn't need a shunt in a sports car while he was trying to win Grands Prix. Carroll Shelby, meanwhile, used the defeat at Le Mans in '63 to persuade Henry Ford to finance the Cobra Daytona Coupe. A sort of American GTO with long nose and tail, coil springs and the same big Ford engine which blew off Ferrari's GT cars at the 1964 Le Mans.

The all-American crew-cut crew of Dan Gurney and Bob Bondurant won the class with fourth overall, just ahead of the ubiquitous Beurlys in a 1964-spec GTO.

These are both GT cars from a golden era where all the things you do for fun on a greasy roundabout were an essential part of every lap. Less a question of tyre compound, wing angle and ride height, more a question of putting the available ingredients together better than the next man. Inspiration in the cockpit could always make you faster. And it's physical. The steering is informative in a way modern racers can't imagine but it's heavy and you have to wedge yourself in different places to use it for different corners, use knees, elbows or whatever as braces because you are not belted to the point of pain in some deep Kevlar bucket. You work all the time and step out sweaty with sore feet and bruises you only find the following morning. You have to work at it, because 40 years down the road these are still massively fast cars in any terms.

A favourite then...? Well, that all depends whether you're asking as a romantic, a racer, or a businessman. Me, I just love driving them.

Thanks to Nick Mason, Ten Tenths, Nigel Hulme and everyone at Goodwood for their help with this feature.