The bobbies have finished setting up the police barriers along the curb in front of the Albert Pub and along the opposite side of the street. Behind the barriers the throng is growing. Conversation is hushed. The expectancy can be felt.

The onlookers, many in black leather jackets and white socks, some sporting carefully greased DAs, clutch their pints of beer, murmur distractedly to their mates and keep their eyes on the Albert Bridge arching over the Thames. Beyond it twinkle the lights of Chelsea.

Across the street the uniformed attendant leaves his post at the Battersea Park gates, saunters over to the barrier and, on tiptoe behind the crowd, gazes nervously up the road. All ears are pricked for that first distant roar of a souped-up V-8.

Twilight settles over London. We wait. Then it comes.

BRRRRRAAAAMM -- VRROOOOMM!

The crowds press to the barrier for a better look as the low, racy shape of a white 1964 premiere Mustang, rear end jacked high over enormous tires, sputters into view. It coasts off the bridge and down the street, pausing in front of the pub momentarily to rev its deafening engine in mock challenge to the police watching from the traffic island. Then, with a squeal of tires and the sharp smell of burning rubber, it shoots around the corner and disappears. The crowd claps and whistles, flashbulbs sparkle like silent gunfire. The bobbies speak into their walkie-talkies.

The rally is under way.

Hard in the wake of the Mustang, rumbling and screeching, comes a steady stream of classic cars. Most of them are souped-up for drag racing. Most of them are American: '57 Chevys, '59 Bel Airs, Model A and T Fords, '38 Plymouths, '56 Mark II Zephyrs, '62 Ford Fairlanes, even a "Straight-8," Brooklyn's racing Bentley. They cruise by majestically, radios blaring. Slowing in front of the car enthusiasts and curious -- or alarmed -- bystanders lining the street, their drivers gun the engines so the chromed exhausts shudder and spit, then maneuver into place behind the ever lengthening parade of wonderful wheels snaking its way across the bridge, up Kings Road where the punks and tourists swarm, then over Chelsea Bridge and back around the park.

But for the dapper, helmeted bobbies, the pub sign swinging in the cool, moist air, and the fact that the cars are all on the wrong side of the road, it might be Saturday night at the soda bar, Anytown, U.S.A., circa 1957.

If you live in London and own an American roadster, chances are you'll show up at Gary's Shack, across the river in Wandsworth. For spare parts, that all-important nitrous oxide injection system for a fast start on the drag strip, or just a tuneup, Gary's is the only garage for many miles around that specializes in American cars. Starting 10 years ago in little more than a parking space, Gary Healey has built his garage into a thriving family business, catering to the needs of the growing number of American car enthusiasts. He is also one of the founding members of the Saturday night rallies, or "cruizes."

A stocky 40-year-old with gray streaked hair and frank, steady eyes, Healey is more than happy to talk about his business, as it is entirely concerned with the love of his life: American cars.

"I grew up in Battersea," he says. "It was a poor neighborhood at that time. Americans living in London used to use Battersea Park for their fireworks and such on the Fourth of July. We kids used to go over there and hang about -- watch the show. The Americans were good to us. They'd invite us over for a beer and stuff. We went nuts over anything American.

"My first car was a '58 Fairlane. Then I got a '64 Mustang, and then a '69 Mustang with a 351 Windsor engine. I called one 'The Boss' and the other 'The American Dream.' They were a matched pair."

Healey wipes the grease from his hands and brings out some photos of various cars he's owned or worked with. His eyes sparkle as talks about each one, detailing the model number, engine type and special features. He talks about them as if they were old lovers.

"About 11 years ago we American car owners started meeting at Battersea Park -- at the Albert -- to cruise around and see what everybody else had. And it began to be a regular thing, the last Saturday of every month. At first the police tried to stop it, but as we didn't have an organizer, they couldn't shut us down.

"But now, of course, it's a regular thing -- in the papers and all. And the tourists come. And ABC did a television thing on us last year. Now the police just hang around and hand out speeding tickets sometimes."

Healey also organizes an annual summer picnic at Pod Raceway. The event gives enthusiasts a chance to show off their machines, and to take a considerable purse for winning the 1/4-mile drag race. This event attracts a growing crowd every year, and is regularly covered in Street Machine magazine.

It is beginning to get quite dark. The cars begin pulling up and parking. The owners, with beer on their minds, find themselves the hub of small circles of admirers. The cars are photographed, inspected, caressed. The owners proudly discuss their wheels and their adventures.

One young man holds forth about his 1970 white Challenger, while his girlfriend, for the time being completely ignored, sits disconsolately on the fender. The young man points out the original blue racing stripe (he has an advertisement from a period American magazine in the glove compartment, in case there is any doubt), the all-new plush interior and the recessed grille.

"I haven't raced it yet," he says, "but I take good care of it and I work on it all the time."

Like most of these car enthusiasts, he probably spends most of his money on the car, too.

As we talk, a Rolls-Royce Silver Ghost glides by, trying to get in on the action. No one is impressed. Halfway down the block the stately limo is rudely passed by a roaring black Chevy pickup with huge tires, flame decals and "The Big Truck" printed along the side. Right behind the Chevy, also whipping around the Rolls, comes a Plymouth Fury, authentically done up as a police car and bearing the legend "Highway Patrol." A cheer goes up. The Rolls slinks away.

The young owner of the Challenger pats the roof lovingly. His girlfriend is nowhere to be seen.

"You've got some great cars over there," he says. "American motors are the best, really the best."

Did y'all hear that, Toyota?