Red Sox fans, their aged passions cooled by the recollection of such torments as the Bambino's bye-bye and Buckner's boot, aren't easily impressed. So it was odd to discover thousands of them, clustered in Fenway Park's box seats an hour before a Boston-Oakland game, oohing and aahing like yokels at their first ball game.

Their focus was the batting cage. An enormous red-haired man in a green shirt, with two-story arm muscles and thighs so thick that his legs resembled inverted bowling pins, stood there swiping at pitches with the fervor of Paul Bunyan.

One blast soared deep into the center-field bleachers, far above a 420-foot sign. "Oooooooohhhhhh!"

From the thunder another ball produced as it smacked against the Green Monster, it must have left a crater the size of a bowling ball. "Aaaahhhhh!"

Then, on the next-to-last batting-practice swing, the ball shot off the bat like a shell from a mortar. The crowd's reaction rose in pitch, to a gasping "Whoooooohhh!"

Still ascending, the ball passed over the left-field wall and the lofty netting atop it, crossed Lansdowne Street, and landed, spectators later claimed, "out near the Mass Pike."

"Finally," said Mark McGwire of the Oakland A's, as if all his previous swings had yielded nothing but dribblers. "It's about time."

*

Mark McGwire is not accustomed to gaps between moon shots. Last year, his ratio of 1 home run for every 8.1 at-bats was the best in baseball history.

This year, entering Wednesday night's game, it was even better, at 1 for every 7.4 at-bats. In his last 162 games - the equivalent of a full season - he had hit 70 homers.

Every night, thanks mostly to McGwire, the A's batting practice is both a show and a message.

"It's always like this in B.P.," said Oakland catcher Terry Steinbach, gesturing toward the crowds. "You see fans watching. And sometimes you see the guys on the other teams watching, too. It has to be a little intimidating to them."

Though his home run pace has slowed in recent days, stalling at 43 homers despite a three-game series here, a healthy McGwire is always a threat to Roger Maris' single-season record of 61.

In fact, McGwire's strength and statistics might make the slugger the greatest threat since the New York Yankees outfielder won his fame and lost his hair in the summer of 1961.

There is not a baseball person alive who does not believe that McGwire, given a season free of injury, can make a serious run at Maris' record. Remember, despite missing 23 games with foot and back problems, he had hit 43 home runs this year in only 98 games.

"The thing that sets him apart," said Oakland manager Art Howe, "is that Mac is so strong, he can hit a ball badly and still drive it out of the park."

Should he ever approach 60 homers, McGwire, 32, knows the media will begin following his every step, detailing his every move, complicating his life. But the distractions that haunted the psychologically frail Maris would likely bounce off the 6-foot-5, 250-pound frame of this mellow Californian.

"I don't concern myself with what-ifs," he said. "If that happens, fine. I'll deal with it."

In other words, his red hair, curled as tightly as he is in the batter's box, will not fall out.

As his pace approached Maris' and the inevitable questions began to be asked - over and over - McGwire casually and politely shrugged them off.

"I have never really even allowed that stuff to get into my thought processes," he said. "How can anyone even speculate on that now? If it were September and I had 50 or more home runs, then maybe. But why now? Besides, this a team game. This is not an individual game."

It's a cliche, but it's one McGwire appears to believe. Despite the great distances his home runs tend to travel, McGwire refuses to stand and watch them, fearful that he might be showing up a pitcher.

"A home run is a home run," he said. "When you think about it, it's only a base hit that goes over the fence."

He is even embarrassed by his father's penchant for taping highlight shows that feature McGwire's home runs and then showing them to the player's four siblings - one of whom, Dan, was an NFL quarterback - whenever they visit.

"They must love that," McGwire said with a laugh.

But surely a man whose hulking body, hurricane swing and humble temperament seem so perfectly adapted to home runs - through Thursday, he had 82 homers and just 69 singles in the last two years - must derive some pleasure from them.

"Well, there is a special feeling that you get when that round ball meets the round part of the bat squarely," he said. "I think it's probably a feeling that only a baseball player at this level can appreciate. It's like a golfer driving one 350 yards or a tennis player getting off a 150 m.p.h. serve. It's just special."

McGwire seems to be having difficulty understanding why Maris' record is so special. Like many professional athletes, he grew up doing, not watching. The outdoors-loving son of a dentist in Pomona, Calif., he preferred being listed in box scores to studying them.

"I think fans on the East Coast are more passionate about sports," he said. "On the West Coast, there was so much else to do that we were more casual. The statistics and all probably didn't mean as much to us.

"Besides, everyone is eager to ask me about 60 and no one asks about 50. There have only been 12 guys who have done that. But 61 is the number everyone wants to focus on."

Another statistic that has dogged McGwire and the rest of the Weight-room Warriors on the rejuvenated A's is their pursuit of the single-season club record for home runs - the 240 hit by Maris' '61 Yankees.

A youthful lineup that pumped up in the off-season weight room - its bulk has given rise to the inevitable questions about steroid use, and to denials - had hit 207 through 130 games.

In addition to McGwire's 43, through Thursday, Geronimo Berroa had hit 34, Steinbach 30, Scott Brosius 21, and Jason Giambi 20.

"I can't speak for the other guys, but I know that in my case, I'm just stronger," Giambi said. "Last year, I started the season at 205 and ended up at 190. This year, I began at 220 and stayed there. And you can't say enough about the influence a guy like Mark has on all the younger guys."

Indeed, Oakland's young sluggers have trailed after McGwire like puppies this season. Giambi even appeared to enjoy being slammed in the face with a shaving-cream pie by McGwire during a pregame interview with ESPN.

"He has been a tremendous influence on the younger guys on this ball club," said Howe, the manager. "When he was out of the lineup, there was a lot of pressure on them. And when he got back, it seemed to disappear."

Free from the shadows of Rickey Henderson, Jose Canseco and the other big personalities from the great Oakland teams of the late 1980s, McGwire has finally assumed a leadership function this season.

"Before, there were always people like Rickey and Jose around, so that wasn't my role to fill. This year, it is. All I know is that I'm enjoying this season more than any other."