Most young racing drivers don't get to drive a wide range of cars. They start in a junior category, such as Formula Ford or Formula Renault, before progressing up the single-seater ladder. Only after they've given up on the F1 dream - or finished their career at the pinnacle of the sport - do some diversify into touring cars or sportscars.
Similarly, many historic racing cars don't get pushed to their limits once past their prime. That's no disrespect to their owners and drivers, for whom historic racing is a hobby not a career, but with the very rare exception they are not on the same level as the best of the up-and-coming talents.
I've always liked the idea of putting the two together: young drivers who push the limits in cool old machinery that is rather more raw than the refined and comfortable cars of today. One of the privileges of working for AUTOSPORT is that you sometimes get to do just that.
Earlier this year we helped F3 Euro Series star Alexander Sims expand his horizons. For a feature, due to appear in AUTOSPORT magazine in the New Year, Sims tested a set of F3 machines at Brands Hatch, from a 1950s 500cc Cooper to a modern Double R Dallara.
Unfortunately, his run in one of the cars - historic racing ace Simon Hadfield's March 743 - was curtailed by red flags. Ever the enthusiast, Hadfield arranged for Sims to drive the car again at Silverstone, prior to the Historic Sports Car Club finals at the Northamptonshire venue.
So it was that Sims, Hadfield's team, and I arrived at the home of the British Grand Prix for no other reason than to see a fantastic car driven by one of the best young British talents.
It might only have been a test day, but as Sims got more and more comfortable he got faster and faster. By the second session, which I viewed from Luffield, he was throwing the car around, controlling its slides and pressing on to such a degree that a modern Formula Renault driver dropped it at Brooklands trying to keep up!
The result was a time comfortably good enough to put Sims on pole for the Classic F3 race at Silverstone the year before. That was good, but things soon got a lot better.
At lunchtime Hadfield called me to see how things were going. On hearing the times, he responded with more enthusiasm and a great offer: "He's got some potential then! Stick him in the F5000 to see what he makes of that."
Along with the March, Hadfield's team had brought along his five-litre Lola T330, for historic sportscar and tin-top ace Graeme Dodd to drive. The 600bhp V8 machine, with massive slicks and (relatively) piddly front wheels was quite a handful, especially for someone with Dodd's lack of single-seater experience.
He'd just about managed to break the 60-second barrier - something achieved by Sims in the F3 March - but his neck was aching and he wasn't happy. Despite the fact he was considering buying the Lola, Dodd agreed to let Sims (whom he'd never met) have a run in the sort of machine raced in period by legends like Jody Scheckter and Brian Redman.
Sims's look as he climbed in was a combination of excitement and apprehension. The Lola was more than twice as powerful as his F3 Dallara and 100bhp more than the DTM Mercedes he drove so well on his way to winning the 2008 McLaren AUTOSPORT BRDC Award. And the aero? Well, it's 1970s aero, not 2000s. It's more a lack of lift than outright downforce.
The car sounded incredible as the Chevy V8 thundered into life and rumbled down the pitlane. Sims waited until the back straight before giving it full beans - and gave himself quite a shock.
"It just goes wwoooaaahhhh," he said afterwards, his arms waving around as he described the oversteer. "There's a bump on the exit of Becketts I've barely noticed before, but in this it just throws you sideways."
Despite masses of traffic and very old tyres, Sims soon got down to the 56s. Dodd shrugged with a wry smile when the team showed him the times, before Sims managed a low 55. It's a time that would have put him on the front row for the following day's Derek Bell Trophy race and, with gaps in traffic being few and far between, he then decided to bring it in, shaking his head with disbelief as he trundled down the pitlane.
"It's absolutely awesome," he said after thanking Dodd. I asked him, of all the cars he's driven, which was the most enjoyable? Surely the grip and power of a DTM Merc, or GT1 Aston Martin trumps the older cars?
"No, it's got to be the Lola and the March," he said. "As a driver you have to do so much more - you have to think about every gear change.
"It must be unbelievable to race them. This is what racing cars should be like."
Some people say that modern racing drivers have it too easy, that they wouldn't be able to cope with the 'real mens' cars of previous eras. Sims helped show that's nonsense. The only thing they lack is the opportunity to prove it on a regular basis.
Now all we need to do is organise a F5000 race for junior drivers in 2011.