The Pittsburgh Pirates are a team of loud noises and large men, huge egos and massive reputations.

Yet tonight, it was the little men of the Bucs -- the sawed-off infielders named Bill Madlock, Tim Foli and Phil Garner who look like bristly throwbacks to 1890s photographs -- who laid a crushing 10-1 defeat on Montreal, pushing the Expos 1 1/2 games behind the Pirates.

The brave, but exhausted, Expos may not be dead yet. But, if there is a baseball justice, they ought to be.

It is conceivable that within 24 hours the Montrealers could be back in a flatfooted tie with the Bucs. But it wouldn't really seem fair.

In the last fortnight, the Pirates have won five of six games head to head by a total score of 40-18, sweeping a pair in Montreal, then winning three of four in this showdown.

"We got thoroughly whipped," said Montreal Manager Dick Williams. "I just wish we could have made it closer. Right now, we're down. But we'll be up in the morning and back at 'em at night."

That has been Montreal's habit all year, yet tonight's lopsided doings ought to convince the Expos that the new, reconstructed Pirates are a stronger outfit. Perhaps, in fact, baseball's strongest gang at the moment.

The reason that the Pirates have made a quantum leap to the realm of truly well-rounded and intimidating teams is the acquisition in Manager Chuck Tanner's three years of a feisty infield of Madlock at third, Foli at short and Garner at second base.

In this series, the stumpy trio reached base 30 times. Tonight, they were a diminutive wrecking crew. Garner drove in three runs with a homer and double, making him perhaps the only No. 8 hitter in baseball with 50 extra base hits. Foli also had three RBI, while Madlock, who reached base a dozen times against the Expos, had a perfect night with two singles, a double and two walks.

"Those three are the little guys who support our big guys," Tanner said, meaning the renowned Willie Stargell and Dave Parker. "They're from the old school, hard nosed guys who beat you and you don't know how."

With Bruce Kison pitching a complete-game seven-hitter this evening -- making his career mark 22-6 in September, the Pirates really might not have needed fireworks. However, it was the Buc hail of 14 hits that salted Montreal's wounds.

"You like to leave an impression," said the spikes-up Madlock, a two-time batting champ. "Especially us nasty little guys. I guess Foli's the tall one (5 foot 10) and Garner's the shortest (5-8). I'm the middle.

Soon after Tanner arrived from Oakland in '77, he traded for Garner. "The other players would tease him," Tanner said. "They'd point at me and say, 'Go cry to your daddy'."

Madlock and Foli became part of "Chuck's Bucs" this year, both being available in trade because of hot-tempered, outspoken reputations in San Francisco and New York, respectively.

"On this team," grins Tanner, "they're considered quiet."

Garner struck the decisive blow of this game, and perhaps delivered the wallop that swung this whole pennant race toward Pittsburgh, with his two-run homer in the fourth.

The Pirates led, 1-0, at that point, but Three Rivers Stadium with its standing room only crowd of 42,043 could feel the eerie vibes.

Expo starter Steve Rogers was squirming out of one jam after another. Sooner or later the defending NL ERA champ might get his act straightened out.

Kison started brilliantly; 19 of his first 20 pitches were strikes. In fact, he did not throw his second "ball" until the third inning. Yet Kison, an excellent cool weather pitcher, has always had blister problems and seldom stays strong an entire game. His pickle-brine home remedies are a legend, but one that makes the Pirates worry in close games.

Garner's homer gave Kison breathing room and seemed to ignite the Bucs, "I don't know why I even swung at that pitch," said Garner. "Madlock was stealing. But it was a high, hanging slider and I guess I just couldn't lay off it."

The crowd roared so long that ole Willie Stargell had to order Garner to go out for a bow. "I don't get too many standing ovations," said Garner, "but I didn't have to be told twice to go out. I felt so tall I could have played middle linebacker for the Steelers."

Then the deluge arrived. For the second night in a row, Pittsburgh scored seven runs in back-to-back innings while sending 17 men to bat during the two frames.

And for the third straight night here, the Expos looked like a drained and battered outfit on its last legs after playing 17 games in 12 days. Now, they must fly all night for a two-night doubleheader Thursday in Atlanta. while the Pirates get to sleep at home before an afternoon game with St. Louis.

As the Pirate run total mounted, the Expos fielded sloppily, missed cut-off men, and generally had that full-retreat look.

The Pirates had many heroes in this make-or-break stand, including Dave Parker who had seven hits, and Ed Ott who had five RBI in the final two games.

Nonetheless, it is the shrimp with the red handlebar mustache at second the eerie fish-eyed lynx at shortstop in high-top shoes, and the barrel-chested and bearded banty rooster at third who have soldered this oncewild Pirate team into a club with the look of a champion.