It's not hard to notice that the Boston Red Sox have an impressive lineup. They lead the league in runs scored (625) and, in a year where just three teams are scoring more than five runs per game, they are scoring five-and-a-half. They are flush with MVP candidates, lead the league in OPS+, and are second in the majors in homers despite playing in a park that depresses them. 

What's more surprising is how well those numbers stack up historically. We're so used to seeing Boston hit that it's easy to take their 2011 season for granted, but, according to both True Average and wRC+, the Red Sox are in line to possibly be the top offense of the last 50 years -- the entirety of the expansion era. 

TAv is Baseball Prospectus's measure for offensive production, scaled to resemble batting average. It's adjusted for park and league contexts, so any team or player from any time period can be compared to one from a dissimilar era without trouble. As for wRC+, it is wOBA adjusted for park and league, and placed on a scale like OPS+: 100 is average, so with a glance you can see how far above or below-average a player or team is. More concisely, both numbers are up to the task of comparing the 2011 Red Sox to teams that came before.

One hundred and fourteen games into the season, the Red Sox rank behind just the 1976 Cincinnati Reds by both measures. While TAv and wRC+ can't agree on which Yankees teams of the last decade-plus are trailing Boston, the two do agree on the top three offenses of the last 50 years:

The 1982 Brewers featured a lineup with Robin Yount at his finest, when the 26-year-old shortstop took home his first MVP honors thanks to a league-leading 367 total bases. He wasn't alone, though. Cecil Cooper hit .313/.342/.528 with 32 homers and 73 extra-base hits; Gorman Thomas hit just .245, but did it with power (39 homers) and patience (84 walks); Ben Oglivie contributed 34 of the team's 216 homers. Four Brewers drove in at least 100 runs, and catcher Ted Simmons just missed making it five. The offense was so stacked that Paul Molitor and his 129 OPS+ looked ordinary.

The 1976 Reds are better known, as this was the Big Red Machine at its biggest, most efficient, and arguably even reddest. They went 102-60 to follow-up their 1975 World Series victory over the Red Sox, and earned a repeat by trouncing the Yankees in four games. Every single lineup regular finished above the league average offensively, as did most of their bench regulars: the "worst" starter was shortstop Dave Concepion, who hit .281/.335/.401 in a year when shortstops combined to hit .246/.308/.312. 

Joe Morgan's 1976 is one of the all-time great seasons. He won his second MVP in a row, picked up a Gold Glove at second, and led the league in both on-base percentage (.444) and slugging (.576). His 186 OPS+ that year just misses top 100 all-time status (190), and this is back when second basemen hit like, well, second basemen (.256/.315/.335). 

The Reds didn't do it with just Morgan, though. As a team, they led in every single major offensive category, except for caught stealing, where they ranked fifth. First in walks, first in hits, first in homers, tops in OPS, led in total bases, and even led in steals. Three Hall of Famer hitters were in this lineup (Morgan, Tony Perez, and Johnny Bench), as well as someone who would be in if not for some gambling problems. 

The Red Sox can't throw Hall of Fame names around like the Reds and Brewers can -- this is an older team, but it isn't that old. They do, however, have a similar situation to the 1976 Reds, in that the rest of the league just isn't hitting, but Boston is, and like crazy. The average team hit .255/.320/.361 in 1976, whereas the Reds were at .280/.357/.424. They were the lone club to score over five runs per game, and not only were they the only team over 800 runs, they crossed the 850 mark, too. 

In 2011, the average team is hitting .254/.320/.395, while the Red Sox are at .282/.354/.458. If not for the Yankees and their .284 TAv and 117 wRC+, Boston would already be ahead of the Reds -- the fact Cincinnati never had a threat as close to them as New York is to Boston is part of the reason they stand alone, as these stats are all relative.

Even with that, though, the Red Sox have just under two months of games left, and are right behind the Reds. They have cut out the dead weight in the lineup, too, so expecting them to keep on hitting -- or even improve -- during that stretch isn't crazy. If that's the case, we're currently watching the greatest offense of the expansion era do its thing.