CHALLENGING MOUNT EQUINOX.

Byline: GEORGE P. BLUMBERG

Drive down southern Vermont's bucolic route 7A on the second weekend of June, and suddenly the crack and rumble of exhausts echo off mountaintops, juxtaposing with green farmed hillsides and the meandering blue ribbon described by the Battenkill River.

Then, at the base of Mount Equinox, in Sunderland, enter a scene out of the 1950s. Vintage race cars gather at checkered flags marking a starting line to roar up Skyline Drive, winding 5.2 miles through 53 turns with an elevation change of 3140 feet. Bugattis, Allards, Bentleys, Indy cars and racing specials have been running this hill since the Carthusian Order of Catholic monks-the silent order that owns it and whose motherhouse in France makes Chartreuse liqueur-first allowed them to do so in 1953.

The hill is just wide enough for two cars, with 20 hairpins and scary drop-offs, and the cars often run in rain and fog this time of year. The Vintage Sports Car Club of America has sanctioned the event since 1973.

"We're low-key,'' says John Schieffelin, the club's president, running a '39 MG TB today. "We don't give trophies; we're just a car club that happens to race.''

The goal is to preserve the cars. Eligible are all pre-World War II sports and race cars, plus select others.

"Low-key'' describes the scene. Racers set up shop under tarps joined to trailers, where they tune and adjust, swapping tools and parts. Spectators mingle with drivers and can observe from Caruso's Turn, a white-knuckle, ...