PRO FOOTBALL

Pittsburgh won its second straight Super Bowl and fourth in six years, but it took a tough battle in which the lead changed hands six times before the steelers subdued Los Angeles 31-19 with a pair of fourth quarter touchdowns.

The underdog Rams took a 7-3 first period lead, off- setting Matt Bahr's 41 -yard field goal with a 59- yard TD drive capped by Cullen Bryant's one-yard plunge. Franco Harris's one-yard scoring run at the end of a 53-yard march put the Steelers back on top, but a pair of field goals by Frank Corral (31 and 45 yards) gave LA a 13-10 halftime edge.

A sensational, leaping catch by Lynn Swann gave Pittsburgh a 47-yard touchdown pass play and a 17-13 lead early in the third quarter, but again the Rams retaliated, with Vince Ferragamo passing 50 yards to Billy Waddy and Lawrence McCutcheon throwing a 24-yard halfback pass to Ron Smith for the score on the next play.

Early in the fourth period Terry Bradshaw and John Stallworth connected on a 73-yard pass play for what proved to be the winning TD, and late in the game the same pair clicked for 45 yards to set up Harris's one-yard plunge for an insurance score.