The Dallas Mavericks have won 50 of their last 55 and are 50–9. It seems only fair to wonder how good this team really is.

The two options are “extremely good” and “historically good,” and while we all hunger to see history in the making (or at least we’re supposed to be starved for historical feats. Doesn’t that explain all these inconsequential stats that are bandied about like the Suns’ supposed quest to go undefeated on the road in interconference play?), the answer looks to be the former.

Fifty wins in 55 games would put Dallas on pace to be one of the best teams in NBA history, but none of its peripheral numbers support the idea that it will maintain that pace. Instead they’re more likely to finish somewhere in the vicinity of 67–15.

Of course, there’s nothing wrong with that; any fans of the local teams should do a Mary Tyler Moore pirouette and toss their hat in the air at the thought of either the Knicks or Nets winning 67 games.

That 67 wins doesn’t get you into the club of historically great teams should give you an idea of how high the bar is set. Here’s a list of the top five single-season teams in NBA history by wins and their average point differential.

Pretty elite company, eh? Four of the five teams won the title, rarely losing en route to the parade. The team that didn’t was the Celtic team, which lost to the ’73 Knicks (who went on to win the title cementing their place in basketball history and New York sports lore).

Dallas isn’t likely to reach this plateau, 50 wins in 55 games notwithstanding. First of all the Mavericks point differential is only — yes only, remember the context — 8.1 points a game. That’s more consistent with a 62 or 63 win season (yes, those ’73 Celtics overachieved, too, and were perhaps due for a fall). However, if I was to stick to my stats with religious zealotry, I’d be arguing that the Mavs are going to go 13–10 in their last 23 games, and anyone with good sense would e-mail me to ask exactly when I figure forward Dirk Nowitzki or guard Jason Terry is going to get hurt so they can place their bets accordingly.

Instead, I’m going to figure that since they have 59 games in the books, their point differential argues that they’ll play only .764 ball the rest of the way. That would yield a 67–15 record. Sixty-seven wins would leave them in the second tier all time.

Not bad company to keep. Dallas fans can also take solace in the fact that all of these teams won the title and four of them stomped their way to the victory parade. (The exception was the ’92 Bulls, who got all they could handle from the Pat Riley-era Knicks.) Dallas fans may want to argue that their boys are racking up their wins in a tougher environment; these other superteams were formed in expansion eras. It’s also true that this year’s NBA includes at least three teams that are tanking to get better draft position, which has resulted in an equally stratified league.

To reach 67 wins, the Mavericks would tail off to a 17–6 finish. Not only is that consistent with their current point differential, but it’s also consistent with other 65-win plus teams who rested their key players down the stretch, losing a meaningless game or two in exchange for entering the playoffs in peak form. The ’97 Bulls lost a game to the Knicks that would have given them back-to-back 70 win seasons. The ’72 Lakers, with 70 wins in sight, lost to the 23–59 Cavaliers during the final week of the season. Once their seeding is assured, teams start eyeing the real prize.

The Mavericks lead the San Antonio Spurs, their divisional archrival, by nine games, or, put another way, the magic number in Dallas is 14 for the division. The Mavs’ lead over the Phoenix Suns for homecourt throughout the playoffs is four games, and the teams play each other twice, next Wednesday and April 1. If form holds, expect Dallas to ease off the pedal sometime during the last week or two of the season and lose a few meaningless games as the chance to redeem last year’s disappointment in the Finals looms.

mjohnson@nysun.com