The eighth season of "Playing Football" for fun and profit -- the emphasis is not necessarily in that order -- begins this weekend. Which means, once again, the streak is on the line. I'm seven up, in a row, straight, successively.

From September 1974 through Super Bowl XV, the imaginary money figure stands at plus $29,654 on an average investment of approximately $400. Pros only are involved, the NFL, with the record revealing 262 winning selections against the point spread, 223 losers. Losing is costly, $11 for every $10 risked.

The break-even point is 52.37 percent, were each selection assigned the same value. That has never been my approach. Instead, each pick is given a specific figure, from a base of $250 to, rarely, $3,000. Never more.

What's in store this season for the fans? Well, in terms of the way the games are to be played, the answer is more of the same. Much more. The offensive dominance of the last three seasons will become even more obvious.

Rules changes introduced in 1978 have had the desired effect, producing cheaper points while reducing the number of cheap shots against the quarterback. Holding by offensive linemen is legal. Creating pressure against the passer by conventional means (without gambling, by sending the linebackers and/or safeties) is almost a thing of the past. Say goodbye to the "People Eaters" and the "Sack Pack." Except, perhaps, in "Doomsday" Dallas.

The 100-point game apparently is the perfect attraction, the collective mind of the league office and the television networks. If that be so, it's only a matter of time.

The latest rules change designed to foster such shenanigans now says a catch does not need to be "absolute" in order to be ruled complete. Less "control" is necessary by the receiver. This will help increase the percentage of completions, no matter how chintzy, or how many fumbles follow the completions.

Cheap points have a leveling tendency. The NFL, in effect, continues to reward mediocrity with its upside-down draft and parity scheduling. The point spread is becoming tighter each season, with double digit differences in the teams' abilities declining steadily. We are almost to the point where there are no bad teams left, no matter how inept the management. But there are no truly superior squads, either. I wonder, over the long term, if this is desirable.

Oakland won the last national title without anyone attempting to compare the Raiders favorably with the great Pittsburgh, Miami or Green Bay teams of the past. Only San Diego and Pittsburgh have the potential to be something special this year, and no one will be shocked if they fail to capture their divisions.

Buffalo, the Steelers and the Chargers should take the AFC divisions, with Oakland and Cleveland the wild cards. In the NFC, Dallas, Detroit and Los Angeles deserve to be divisional favorites, with Philadelphia and Atlanta the wild-card qualifiers.

What is easier to predict is that '81 will turn out to be the most crowd-pleasing season in NFL history as the stadium scoreboards glow with the record point production.

Washington is a prime example. Long gone is George Allen. Gone is Jack Pardee. Joe Gibbs is in charge, a coach for the '80s if ever there was one. Gibbs' strategy is to give up three points, if you have to, in order to get the ball back and go for seven. Many fans approve. They would rather lose, 34-31, with Gibbs than win, 7-6, with Allen, and they are typical of hundreds of thousands of armchair athletes throughout the nation. To them, it's not whether you win or lose that counts, it's how you attack the game.

The irony, however, is that Pardee's winding up in San Diego, as defensive coordinator for Don Coryell, might make the Chargers the winning team in Pontiac Stadium on Jan. 24.

I continue to attack my selections primarily on the basis of line-play matchups. If I can predict what will happen on the line of scrimmage, the job of predicting the winner is much easier. The only change in the approach from seven years ago is that increased emphasis is now accorded the offensive line. From '74 through '77, defenses dominated.

Pittsburgh gets the first week's biggest play, an imaginary $500 at home, giving 8 1/2 against Kansas City. K.C. has quarterback miseries, and the Steelers should shut down the Chiefs' running game. Two other home teams attract $250 each: Denver getting 2 1/2 against Oakland and Cleveland giving one Monday night against San Diego.