Off a nondescript side street on Stratford's west side is an astounding treasure trove of automotive masterpieces. It's not a car museum, although, to be sure, there are plenty of car museums that wish they had a collection like this. It's Automotive Restorations Inc., which, as its name suggests, is in the business of taking four-wheeled basket cases and transforming them into the glorious machines they were back in the days before gas stations sold milk. "Interest in restoring cars is growing at a rate that's phenomenal," said Kent S. Bain, who owns and runs the business. He said, in many ways, a car is a work of art. "It's a pot from ancient Egypt and a Louis XIV chair."

ARI, founded in 1978, has about 80 cars in the shop at any time, all in various restoration processes. Some are getting painted, and some are having their instrument gauges rebuilt, some are getting new upholstery. Although the company has a small number of cars for sale, just about all of the work is for clients.

The company has about 35 employees, all experts in a particular aspect of restoration -- rebuilding gearboxes, painting, rust repair, upholstery, and so forth. Then there are the little bits and pieces that have to be chased down or fabricated. It's the very same car that their father or grandfather drove for some clients, and they would like to drive it, too. For others, it's a particularly coveted car they want to be brought back to the condition that it was in on the day it left the factory or maybe the day it raced at Le Mans.

"Some clients want the car brought back to new condition, but a lot of them are looking for something that they can drive and enjoy," said Bain, 64. The cavernous shop has its share of Porsches, MGs, Jaguars, Aston Martins, and Lamborghinis. Others are beyond rare, like the once-sad Pegaso sports car near completion during a recent visit. Only 70 were built between 1951 and 1958.

A green -- not British racing green, Bain was quick to mention -- Jaguar E-Type roadster was sitting on jack stands, its floor pan clean enough to eat dinner off. "This is a car that the client really wants to enjoy, so we're making a few improvements," Bain said. "Now, the E-Type had an issue with the copper heater plumbing. It would corrode through sooner or later, and the owner would have a puddle under the middle of the car, wondering where the heck it came from."

The solution, he said, is to replace the factory heater tubing with an all-stainless-steel assembly. The car was also getting a vastly improved and lighter aluminum radiator. "Better than new," Bain said, admiring the car, still in pieces. He said it wouldn't be precisely authentic, but the client is looking for a car that he can have fun with, not a "trailer queen" that only sees the light of day at car shows.

ARI restores its share of trailer queens, too, and many of these fussed-over cars will be at Lime Rock Park in Lakeville over the Labor Day weekend, celebrating the racetrack's 32nd annual Historic Festival. Some will be raced, and others, the prettier ones, will get to appear in the festival's Concours D'Elegance.

A concours is a little like an A-list party for cars. Your car can't attend unless it has been invited. "This place is amazing," said Skip Barber, the former sports car racer whose world-famous driving school operates at Lime Rock and who is also president of the track. "I walk in this place, and I see all of these amazing cars. I figure that they're just being stored here, but no -- they're being worked on. All of them."

ARI takes a different approach when it race-preps a historic car. The driver's compartment has to withstand a crash, and there's fire-suppression gear and competition seat belts required, too. Through its subsidiary, Vintage Racing Services Inc, the company also provides trackside support at vintage racing events worldwide.

"We love real cars," said Murray Smith, the Lime Rock's Vintage Festival organizer. "I have a car being restored here right now. And every time you come here, you see something fantastic. Look at the little Alfa when you came in the door -- it's been driven in the Targa Florio three times. It still has the Targa sticker on the windscreen."

Lime Rock officials say Bain's support and expertise have been pivotal in the LRP Vintage Festival's success over the years. They don't just work on European sports cars. ARI also takes in American iron, motorcycles, and the occasional farm tractor.

So how much does a restoration job cost? Bain said it's not uncommon for a client to write out a check for $150,000 or more -- often much more than what he paid for the machine in the first place. Clients are charged depending on how many hours are needed to complete the job.

"Sometimes, they'll have a car that, frankly, isn't worth that much in the first place, and it still needs a lot of work," Bain said. "I'm honest with them, and I tell them that I can find the same car that can be brought back for a lot less. We never say we can't. We'll say, `It's not a smart idea.' "

Still, spending a small fortune on restoration isn't entirely a gentleman's folly. "You can spend $200,000 on a new car or $200,000 on a restoration," Bain said. "The difference is, the new car will drop in value, but the value of the restored car can only go up." jburgeson@ctpost.com; 203-330-6403; http://twitter.com/johnburgeson