Now the waiting begins.

The Redskins and the Cowboys have finished their pregame preparations for the big showdown in Dallas Sunday. There is nothing left to do but to review, to talk and to kill time.

"Wish we could play the game today," Redskin Coach Jack Pardee said yesterday following his club's final full-scale practice of the regular season. y"We're ready and I'm sure they are."

This has been an interesting week of psychological twists and turns. Pardee began by refraining from taking verbal shots at the Cowboys while Dallas Coach Tom Landry uncharchteristically delivered a few salvos in Washington's direction.

The Cowboy players were quick to mention how the Redskins kicked a last-minute field goad in a 34-20 Washington win in RFK Stadium a month ago. Those three points gave Dallas an early edge in the talking war.

But now, late in the week, things have swung Washington's way a bit. A surprising point spread, which makes the Redskings nine-point underdogs, and one questionable Pro Bowl selection have given Pardee's club new incentive.

Besides, according to fullback John Riggins, "the only edge the Cowboys really have is the home field. It would be a dead-even game on a neutral field.

"It used to be you were playing the uniforms, not the players. There was an aura about them that doesn't exist any more. Before, if you had put the same players in St. Louis Cardinal uniforms, they'd have lost a lot more games.

"It was like playing a national institution, a Notre Dame or USC. They've lost what they've worked the hardest to get; their reputation."

But while his players wait, Pardee isn't taking any chances. For the first time this season, the Redskins will practice at the site of an away game today, just to make sure "that no one is staring at the sky and the dome on Sunday instead of playing.

"We want to get the first look at the field and the stadium out of the way on Saturday, not Sunday. When we show up on Sunday, we want everyone working on the task at hand."

For the younger Redskins, Texas Stadium could be disconcerting at first. The artificial turf is slippery and the way the light breaks through the split in the roof causes an unusual effect.

"It takes a few minutes to get used to the stadium," said safety Mark Murphy, making his third trip to Texas. "The field isn't that great and you have a lot of shadows. There is a definite home-field advantage for the Cowboys. I think it's a good idea to go down there and let everyone see it." c

The younger players have been asking questions all week about this game and this opponent. They've heard about the noise level and that slippery field, but they also keep hearing Pardee talking daily about how the Cowboys "are a team just like the rest of us, they aren't unusual."

At least for rookie tight-end Don Warren, Pardee has won the mental battle.

"I'm anxious to see the place but I'm more anxious to play them," he said. "I've been in big games before from high school on. They are great. I can really get psyched for them."

Pardee really isn't in a great rush to get his players to Dallas. The buildup in Washington this week for the game has been exciting for both him and his athletes and they have loved every moment.

Posters signed by fans have poured into Redskin Park, along with letters and telegrams. Newspaper articles have been tacked up on bulletin boards, players have been besieged for interviews and, as Pardee said, "every time you pick up a paper or turn on the radio, they are talking about the Redskins and Cowboys.

"It's a plus for us. We know people are behind us. It's a great feeling, to see this town pulling for us like they are."

Even Washington Mayor Marion Barry has gotten involved. He made a bet yesterday with Dallas Mayor Bob Folsom. If the Redskins win, Barry gets a 10-gallon hat and a batch of Texas pecans. If the Cowboys win, Folsom gets an Indian headdress and a cherry tree.

Barry says the hat should be one size larger than he normally wears -- in order to account for a swelled head after a Redskin victory.

For Barry to win his bet, the Redskins will have to produce what Pardee describes as "our best game of the year." And that most likely will mean the offense will have to continue its fine play of recent weeks.

After a midseason slump, Washington's attack has finished with a flourish, falling off only against the Giants in New Jersey.

As a result, it has become the most powerful Redskin offense since 1975 and the best-balanced since the early 1970s, the height of the George Allen era.

A comparison with Allen's last team in 1977 illustrates the unit's development under the offensive coordinator, Joe Walton, a backfield coach on Allen's staff.

This club is averaging 302 yards total offense per game, compared to 258 in 1977. It gains 141 yards running and 160 passing per contest compared to 125 and 133 in 1977. And it averages 20 points every time out compared to 14 two years ago.

Allen's final squad (which played only 14 games), didn't produce a 1,000-yard rusher Mike Thomas has 806 yards) and Billy Kilmer passed for only 1,187 yards. This year, John Riggins already is over the 1,000-yard mark (1,oo2) and Joe Theismann has thrown for 2,597 yards, best by a Redskin quarterback this decade.

The balance produced by Walton's tactics are exemplified by Washington's scoring. The Redskins have 14 rushing touchdowns and 19 by passing. In 1977, the team managed only four scores on the ground while scoring 15 through the air. It had only four receivers with 20 or more receptions, compared to seven this year.

"What I like best about this offense," Pardee said, "is we don't rely on the big plays like we had to last year. They are great when they work but they are so iffy. This year, we are more physical and we play the percentages so much better."

The Redskins also lost twice to Dallas in 1977, scoring only 23 total points.

"We've come a long way since then," Walton said. "In fact, we've come a long way in one year. I just hope we have one more good game left."

Although Buddy Hardeman will make the trip to Dallas, it seems unlikely he will be activated for the game. Pardee, however, will wait until today to make a final decision . . . The Redskins also are taking with them to Dallas all the injured players who have been at Redskin Park during the season . . . If practices are any indication, Washington should be ready for a peak performance. This was by far the best week of workouts the club has had all season . . . Pardee says the Cowboys are nine-point favorites "because it is a home game and they are the Cowboys. No, I don't think it's a reflection on our team." . . . No change was reported in the Dallas injury situation but Pardee expecxts Tony Dorsett, Robert Newhouse and Drew Pearson to play.