Al Unser won the eighth annual Schaefer 500-mile race, giving him an unprecedented sweep of three successive events in Indianapolis-car racing's triple crown, and said he "lucked out" yesterday.

Unser, winner of the California 500 last fall and the Indianapolis 500 a month ago, finished 24.5 seconds ahead of Johnny Rutherford, who bumped into and nosed out defending Schaefer champion Tom Sneva on the final lap. They were the only drivers to complete 200 laps around Pocono International Raceway's 2 1/2-mile trioval.

Unser's speed was 142.26 miles per hour, well under Rutherford's record of 156.7 set in 1974.

Unser won because he made only nine pit stops to Rutherford's dozen and Sneva's 14 halts.

"We didn't change the Goodyears all race, the victor said. "I was amazed, but that's a decision not up to me. My crew decides."

He brought his First National City Special into the pits for the last time with 58 miles to go running in third place. Sneva was in the lead but pitted for fuel, allowing Rutherford to move ahead by three seconds.

Rutherford had to stop for fuel with 25 miles to go. Unser had then gone into second, trailed by Sneva, and took over the lead with Rutherford's car in the pits.

Sneva's racer touched wheels with Rutherford's car on the final lap, and Rutherford passed him for runner-up spot.

In fourth, two laps behind, was Wally Dallenbach, followed by Larry Dickson. The first five cars used English Cosworth engines. The first major American victory scored by this engine was Unser's other Pocono win, in 1976.

The 117 miles of the race driven under the cauiton flag for various minor mishaps didn't bother Unser. "It gives a guy a chance to relax," he said.

Cars travel about 100 miles per hour during those periods. "It helps a lot with fuel mileage, too. Less chance of running out when you have to run slow that long," he said.

What did bother Unser, 38, was the rough track.

"Turn two (of the three-cornered track) was very bumpy," he related. "It made it very hazardous there. I was surprised the tires held up." Unser did not comment when reminded the second turn had been repaved for tis race.

All the yellow flags came within the first 250 miles. The slaw pace allowed several machines to be towed in worked on and returned to action.

Danny Ongais, the race's fastest qualifier; A.J. Foyt and Gordon Johncock led for varying periods during the race's first half. The leaders margine were never more than three seconds; the frequent cauflags prevented any driver from establishing dominant position.

Unser was never out of the top 10 during this time. He had qualified rather poorly, 10th of 33 starters, but moved up steadily through the field by halfway.

The race began to develop at 275 miles. Ongals went into the lend again and was not being seriously challenged. At 325 miles, a three-second lead. Ongais glided to a stop on the homestretch with a broken transmission.

"Danny was running well, but I could keep up with him," said Unser a few laps after Ongais dropped out, Unser regained the lead for 50 miles only to lose it to Rutherford when he pitted.

The race now involved only the three leaders. All other contenders, led by Foyt, were at least a lap behind. With 25 miles to go, Foyt was out with engine trouble. Sneva's pit stop, then Rutherford's, cost them their positions and all Unser needed to do was finish.

Only nine cars were running at the end. Among the nonfinishers were Mario Andretti, out after 182 miles when his engine stalled; Bobby Unser, out at 290 miles with broken suspension, and Johnoock, 415 miles, engin troubl.

Rick Mears, winner of last week's Milwaukee 150-miler, was not entered. "Our program laid out a year ago did not include this race for Rick," explained our owner Roger Penske's spokesman. Janet Guthrie's car is being used for a promotion tour and she was not entered.

Car owners and drivers attributed the low number of finishers to the heavy racing schedule this year. This is the fourth championship race within five weeks. "It's a lot of racing; too much perhaps," said chief mechanic George Bigotti, who saw his cars for Steve Krisiloff and Johnoock break down.

Winner Unser agreed, "It was a hard day's work. But it couldn't have been too hard because I won."