In baseball, men who have almost nothing in common become linked for life, and even beyond their lives, because of a common pursuit of the same record.

Babe Ruth and Hank Aaron, for instance, might hardly know what to say to each other if they met in heaven or elsewhere, so different were their backgrounds, their temperaments, their playing styles. Yet, as the only men with 700 home runs, their baseball identities are entwined.

Out of millions who have played or tried to play the game, two who separate themselves from all the rest are bound by an immortal cord. That's why we might as well get accustomed to linking the careers of Nolan Ryan and Steve Carlton.

This spring, both men passed Walter Johnson's career mark of 3,508 strikeouts, one of those records, like Ruth's 714 homers or Ty Cobb's 4,191 hits, which, for generations, seemed an ineradicable baseball monument.

Now, the Ryan Express and Lefty the Sphinx are knotted in an endurance test that may take them to 5,000 strikeouts and beyond. In Philadelphia's Veterans Stadium, a large sign on the left field mezzanine read the other night: "Lefty's K's: 3,587. Nolan Ryan: 3,583."

The two have already passed, and repassed each other several times. "It'll probably go on for years," said Ryan, 36, on Monday. Neither he, nor Carlton, 39, plans to retire in the near future.

To link these men seems, at first, bizarre.

Ryan is relaxed, quietly genial and as close to humble as a fellow with five no-hitters is likely to be; he's much like the Big Train in his easy, grateful acceptance of inexpressible gifts.

Ryan carries the spaces and silences of Texas with him, much as Johnson o have had a Kansas soul.

It wasn't until his 15th season that Ryan gave evidence of pitching maturity; til great thrower.

His record entering 1981 was 178-169; since, it's 36-20.

"For years, teams would sit bacfor me to get myself in trouble in one bad inning; and I did, on a lot of occasions," said Ryan, 9-3 this yearink that I've changed my style. I pitch the same as always. It's just that now my control is better, particula It's a matter of learning over the years, sensing how to get the right rhythm, the right release point . . . hes now, get ahead of more hitters. I try to keep us in the game, not give up more than one run in an inning."

By contrast, Carlton is neof phobias and quirks. This fellow with 294 victories--and 99 more victories than losses--is an intense cerebralnity and huge need to control his athletic environment.

Despite coming from opposite ends of the spectrum oies, despite Carlton's love of craft and Ryan's passion for power, these two larger-than-life hurlers--the gameand righty--are linked in the minds of those who must face them.

"I've played with or against Catfish Hunterm Palmer, Fergy Jenkins, Don Sutton and Gaylord Perry; how's that for one career?" says Houston third baseman an and Carlton are a cut above.

"I don't mean that they're better winners, but they're different. Carlton'swatch him work. There's an idea behind everything. Nolan, I'd pay to watch because if his first curve ball of strike, I think, 'No-hitter tonight?' "

Ryan and Carlton bring a unique dimension to their war with hittertorious, but they vanquish.

"There's no pitcher like Nolan Ryan," said two-time MVP Mike Schmidt. "No one h fast ball and curve. That damn curve gets in your mind. His release point is right in your ear. I listen for en I know it's a fast ball. But by the time I hear the grunt, it's too late to swing.

"Usually, I take his e a miracle if I hit it. And I swing lightly at his fast ball. If you grip the bat tight against him, it's hopeless," says Schmidt, whose three career hits off Ryan are all homers.

ntin' the days, hoping we miss him (in the rotation) . . . To me, he's the ultimate challenge in the game."

"The thing people don't know is that their breakills are what make 'em so special," says Pete Rose. "Ryan has the best curve in the league and Carlton has the best slider.

"Jeez, look at the strength in Ryan's legs," says Rose, gesturinyan who is running his pregame miles in shorts. "The push off is where he gets his speed. And Carlton, becauseund conditioning programs, is the strongest individual in the whole league.

"They're both super competitorss record (for NL hits) off Ryan. You could just see him pull up his belt. He wasn't going to let me get the reays Rose. "He struck me out the next three times. Just forget about it. I didn't even swing at his curve ballsbreak my bat. It's no disgrace to be struck out by Ryan. You got company."

"All the (seven) pitchers with 3 had good breaking balls. That's their common denominator," says Ryan, who never saw the curveless Johnson. "There've been bunches of guys with great ls who didn't do very much. It's your breaking ball that makes the difference, and gets you over the hump. Now, I always establish that I have) early."

"Carlton told me the other day that, in the mid-70s, he went to the slider, not the fast ball, " says Joe Morgan. "Now, 80 percent of his strikeouts are on sliders or curves."

Rose says, "Carlton will ere strikeouts, because, even though he's three years older, he'll pitch longer. Just wait and see."

Whoever, there's really no dispute about the king of K's.

It's Ryan.

Johnson pitched 5,924 innings. Carlton hasbuilt his record in 3,426 innings.

Ryan isn't one of the game's great winners. But no man was ever so hard to hit. His strikeouts (9.43) and hits (6.44) per nine innings are the best ever, edging Sandy Koufax who, because of his fine control, was the better pitcher.

Ryan's uniqueness--his claim to a place in lore and in Cooperstown--is esthetic. Strategy and, some would say, even common sense, were beneath him for 3,000 innings. He thought a pitcher's job was to make the batter miss the ball and there his theory of the sport ended.

Carlton, the thinker, has been the better blend of artist and pragmatist.

These two, so similar yet so opposite, like mirror images, will go down together as the right and left hand of their pitching era.