TOM McCLOSKEY, a big hitter in the construction business, purchased the 1973 expansion franchise that became known as the Philadelphia Atoms for $25,000. As the Cinderella champions of the North American Soccer League gather for their 30th anniversary reunion tomorrow at the Phoenix Sports Club in Feasterville, it is more than safe to say that the value of their memories has increased astronomically.

"When I was hired as the coach, in February of '73, we had no stadium in which to play, no practice facility, no team colors, no uniforms, nothing," recalled Al Miller, who emerged as the league's coach of the year that season. "But I was young enough, maybe 37, 38, and naïve enough to believe we could do it. If you asked me if something like that could be done today, I'd probably say you were crazy."

But Miller and general manager Bob Ehlinger brought over three players - Chris Dunleavy, Andy Provan and Jim Fryatt - from Southport, a third-division team in England, and blended them with a group of young, eager Americans. They built a record of 9-2-8, won the Eastern Division title, set a league record for fewest goals allowed in a season (14), surprised Toronto, 3-0, in the playoffs, then stunned Dallas, 2-0, in Texas Stadium to win the championship.

In the four seasons of their existence, the Atoms never again had a winning record. Before the 1976 season, they were purchased by a group from Mexico. After that season, the franchise went into receivership.

"But we did get rings in '73," said Miller, now the president of the Chamber of Commerce in Wooster, Ohio. "In fact, Derek Trevis, our late captain, lost his while he was living in Blackwood, N.J. He told me he thought he had inadvertently tossed it in the garbage. He jumped in the Dumpster outside the apartment, rooted around until he found it. He said he smelled bad for 3 days."

The Atoms will begin their 30th reunion with a memorial service for Trevis. After that, they will unfurl their memories. Bob Rigby, their goalkeeper from Ridley Township, vaulted on to the cover of Sports Illustrated. Bobby Smith, their defender from Rider College, wore No. 73 for much of the remainder of his career as a tribute to that shining season. Fryatt, their burly striker, sang "The Star-Spangled Banner'' before one of the games as a way of giving something back to the community.

"Jim had always sung along before every game, sort of under his breath," Miller said. "When he asked me if he could do that, I didn't know he could carry a tune."

Miller had earned an NCAA Atlantic Regional ring coaching New Paltz State, and later won three rings as a co-founder, president and general manager of the Cleveland Crunch in the Major Indoor Soccer League and the National Professional Soccer League, but his Atoms ring - which he has since presented to his daughter, Karen Jurgensen - remains his most precious.

"To think we could have done what we did that season is unbelievable," Miller said. "But even more unbelievable has been that we've been able to stay connected through all the years. When I was told that Fred Shero had written on the Flyers' blackboard, 'Win today and walk together forever' before they won their first Stanley Cup, I put that in my letter to our players."

He found all the players other than Dunleavy, saying, "I was told he was somewhere in Australia, but I couldn't locate him." Amazingly, because Dunleavy had been serving a suspension in England, he had been able to play in the Atoms' Aug. 25 title game. Provan, nicknamed "The Flea" by Daily News columnist Stan Hochman, and Fryatt returned to Southport that day, the English team insisting that the terms of their loan arrangement could not be extended. Charlie Duccilli and Bill Straub became emergency starters against the Tornado. Duccilli had appeared in four games all season. Straub, a defender who had not played a minute after being acquired from Montreal, stepped in as Fryatt's replacement on the front line and scored a goal.

"I took the uniforms for Andy and Jim with us to Dallas, hoping something could change at the last minute," Miller recalled. "I negotiated like crazy with the Southport coach, but he wouldn't allow it. Dallas was in a similar position with a couple of their players and another team over there. You look back now and wonder how a situation like that could happen, but, really, when we put our team together I never thought we could be in a position to get that far that fast."

Reality set in when the Atoms shut out Toronto in the playoff semifinals in front of 18,766 at Veterans Stadium. The title game, everyone knew, would be on the road.

"We went off the field waving to the fans, but when we got in the locker room, Bob Ehlinger told us we had to go back out," Miller said. "The fans were still there, singing 'Auld Lang Syne' to us. All the time that has passed, that's something that has stayed with me."