An event that perfectly captures cool car culture has transformed heaps in four decades - as has the sport of hot rodding - but its popularity remains solid.

Next Saturday's (August 6) gathering at Manfeild stadium is the 40th swapmeet and hot rod display run by the Palmerston North Hot Rod Club and is a world away from the first.

"There were just six sellers in The Square in Palmerston North that first year," recounted club president Tony Denzel.

And last year's not only was the stadium packed out, but so too the extensive carparks, while the crowd was simply too big to count.

The 2011 meet, sponsored by Chuck Restoration Supplies of Auckland, will be equally mega, attracting thousands of enthusiasts flocking from throughout the country.

A hundred display cars with 40-plus trade stalls are indoors. Outside in the carpark area a whole lot more sales tables with new and secondhand automotive parts, plus more hot rods on show in the arena area.

"It's a great day for anyone with an interest in cars," says Manfeild chief executive Heather Verry.

"There's a huge and diverse range of memorabilia at the stalls, but you can spend just as much time looking at the vehicles and thinking about how much time, effort and money went into them."

The gathering's emerging popularity as a car show accelerated after the club's move from Palmerston North Trotting Club Track to Manfeild's massive stadium four years ago.

The stadium has been acknowledged as being a fantastic display space and everyone agrees the cars look great under the lights. The outside all-weather equestrian warm-up surfaces also prove brilliant stables for a different kind of horsepower.

"We'll have 100 cars inside and a couple of hundred more lined up outside. It'll be awesome," Mr Denzel said.

The dream line-up of vintage, souped-up, tricked-out, beautiful and bad-boy automobiles runs the full gambit: Hot Rods, Customs, Muscle Cars, Street Machines, Classic Trucks and Lowriders.

When Mr Denzel and fellow clubbie Kerry Keeys came out for a pre-event look-see, they came in cars that neatly reflect the breadth of interest that exists in modern hot-rodding.

Mrs Keeys' drives an American classic: Her 1951 Ford Mercury came to New Zealand new. Back then the type was an elite brand, favoured for high-level Government officials. Prime Minister Sir Keith Holyoake had one.

This example subsequently went to a couple of blokes in Timaru for 30 years then found its way to Feilding, where the metamorphosis into a hotrod started in earnest. It was half completed when the current owner took over. It's now a grumbling, air-suspended, seal-scraper powered by a 350 Chevrolet, finished in an alluring satin blue.

"I swapped it for a 1951 Chevy convertible," Mrs Keeys said. "My husband, Jimmy, basically spent six month's solid work on it."

The car's attraction? "Oh, I just really like Mercurys from that era. There's just something about them." They've since bought a second car from the period.

Mr Denzel's car, though also a rare gem of a bygone age - just 16,000 pillarless four-door Ford Galaxie sedans were produced in 1964 - is a more recent import.

Landed four years ago from Burbank, California, where it had one owner who clocked around 100,000kms, it is an example of a growing trend to buy ex-overseas cars that are generally in excellent running order.

"It's just run in," he quipped. "We've got every receipt for every cent the original owner spent. Since it came in we've really only had to pay for ongoing maintenance and a repaint."

The gates open at 8am - there's always an early-bird crowd - and the day goes until 2pm.

There's a $10 adult entry fee (kids under 15 admitted free). No pets allowed.