Stephone Paige, 24, a former free agent who never had had a 100-yard game in the NFL, caught eight passes for 309 yards yesterday in Kansas City, Mo., to break the league's 40-year-old reception yardage record.

Even rival defensive backs congratulated him after he had led the Chiefs to a 38-34 victory over the San Diego Chargers.

"They came up to me and said 'Nice job, nice job,' " he said.

The record had been 303 yards, set Nov. 22, 1945, by Jim Benton of the Cleveland Rams.

Touchdown passes of 56 and 84 yards helped Paige total 258 yards by halftime, breaking the Chiefs' full-game record of 213 set by Curtis McClinton in 1965. But Paige went to the bench hurt after catching a 39-yarder in the third quarter.

"I knew about the team record," he said later, "but I had no idea what the league record was. Henry Marshall first told me about it. He came up kind of nonchalantly and said, 'Do you know you need only seven yards for the record?' I said, 'I've already got the record.' Then he said, 'No, I mean the pro football record.' My ribs really hurt, but when I found out how close I was, my ribs stopped hurting. I just sucked it up and went for it."

Wearing a flak jacket, he set the record in the fourth period with a 12-yard catch, his shortest of the game. He said that, "for some reason," the Chargers' safety man "wouldn't move. He'd stay there. I'd . . . run right past him."

"It was just a matter of blown coverages," safety Gill Byrd of the Chargers said.

Lionel James of the Chargers had 242 all-purpose yards for a season total of 2,535. That broke the NFL record of 2,462 set by Terry Metcalf of the St. Louis Cardinals in 1975. Falcons 16, Saints 10

Atlanta's Gerald Riggs gained 157 yards in New Orleans to regain the NFL's rushing lead at least for a day.

He has 1,718 yards this season. But Marcus Allen of the Los Angeles Raiders can win the rushing title by getting 83 yards tonight against the Los Angeles Rams. Riggs easily beat the Falcons record set two years ago by William Andrews, who had 1,566. Packers 20, Buccaneers 17

In Tampa, Fla., Green Bay finished with its third straight 8-8 record, but Tampa won the right to pick first in next spring's draft. Eagles 37, Vikings 35

Paul McFadden's three field goals in Minneapolis included a 35-yarder with 40 seconds left that gave interim coach Fred Bruney a successful debut.

It was the finale for 19-year veteran Jan Stenerud, 43, of the Vikings. His 373 field goals are an NFL record. He did not try a field goal and was five for five on extra points. His 1,699 career points are exceeded only by George Blanda's 2,002. Colts 34, Oilers 16

In Indianapolis, Mike Pagel passed for three touchdowns for the Colts, who hadn't won consecutively for two years.