When Carlo Grippo blized his 800-meter opposition in Milan Thursday, he was cheered by a gathering of 50 persons. Barring a blizzard, more than 200 times that number will be present at Cole Field House Friday night when the Italian Olympian competes in the Carl Joyce 880-yard run at the 10th National Invitational Indoor meet.

"This is the first time I'll run indoors seriously," said Grippo, who celebrated his 22nd birthday Saturday. "In Italy we run indoors to prepare for the outdoor season. Here, I am told , the public is more interested in the indoors than the outdoors."

Grippo and teammate Vittorio Fontanella, a miler, will compete in four American meets, examine their accomplishments and possibly stay a while longer. Since Grippo is serving with the national police, he need only submit a by your leave.

"For me this is very important," Grippo said. "It is the first time that I run indoors with stronger people. In Italy I am No. 1 and Vittorio here is No. 2 and I am first by three seconds in the 800 metres. Nobody is going with me when I run."

Grippo, despite his customary solitude, is unlikely to be psyched out by either the competition or the large crowd here. He ran with tougher foes before a much larger gathering in Montreal in July, when he reached the final of the 800 meters.

"A week before the Olympics I was 21st in the world," he said. "Then I ran 1:45.3 in our national championships and suddenly I was No. 4. Montreal was the first time I was among the best of the world and everybody was asking, "Who is Grippo?"

In the final, Grippo finished last, 50 yards behind Alberto Juantorena's world-record victory, but there were extenuating circumstances.

"It was very difficult in my heat." Grippo said. "I was with Juantorena and I was afraid, because only two from each heat went to the semifinals. But I did get second place.

"In the semifinal I ran against your Rick Wohlhuter (in the race in which Wohlhuter was first disqualified for pushing, then reinstated.) I was always the last, and they push at me, and I thought at 630 meters I was out of the final. But I found a short way through while they were all on the exterior four lanes wide, and I reach the final. It meant so much to me.

"Afterward the semifinal I was in the antidoping for five hours. The man was staying there looking at me and the empty bottle and I could not do anything. I finally went out at 12 o'clock at night without dining after drinking 50 glass of beer and juice and water.

"The final (the next day) was too hard for me after that and running two such races in two days. My nerve had done enough just to get here."

The record Juantorena shattered by two-tenths of a second was 1:43.7, established in 1973 by Grippo's countryman Mercello Fiassonaro. Now 28, Fiassonaro is a rugby player and Italians regard him as a hero, "like a [WORD ILLEGIBLE] or a leading sportsman," said Grippo, "but they have exploited him. He has no money, no aim. If I am at 24 what he is at 28, I will kill myself."

Such a fate is unlikely. After fulfilling his police duty, Grippo will complete studies for his university degree while employed by the Fiat automobile company. Should he tire of the car business, there is always diplomacy. His father is assigned to the Italian embassy in Brussels and it was in Belgium, at age 13, that Grippo first began to run.

Many Europeans have difficulty adapting to American board tracks. Grippo's electronically timed 1:49.37 for the 800 meters in Milan was acomplished on a 200-meter Tartan track with only slight banking. Friday at Cole he will run five yards father on a 160-yard board track with steeply hanked turns. Further, he faces some double teaming.

The opposition includes Villanova grad Ken Schappert and current Wildcat Mark Belger, 2-3 behind Wohlhuter here last year, and Florida Track Club vetern Byron Dyce of Jamaica and current Floridian Wesley Maiyo of Kenya.

It is a most challenging assignment, yet Grippo is not fretting. There is no Juantorena and, more important, no empty bottle waiting at the finish line.

Pole vaulter Dan Ripley, who announced his retirement after failing to clear a height in the Olympic Trials, returned because "I love to vault, I like to travel, I enjoy the competition and the exvitement of competing." Ripley, who holds the amateur indoor record of 18-3 3/4, thinks 19 feet is "a definite possibility . . .When the Russians announced they were sending woman sprinter Tatyana proroclienko to compete in eastern indoor meets, national Invitational meet director Bob Comstock demanded either Tatyana Kazankina or Ludmila Bragina, the distance stars, instead. The Soviet team arrived yesterday and there was Prorochenko, along with the information that Kazankina and Bragina were ill. Pole vaulter Vladimir Kishkun stayed home with an injury, as did Valeri Borzov, who was scheduled to run on the West Coast . . . Ripley and others in the National Invitational field are scheduled for an 11:30 flight to Los Angeles Friday night, so they can compete in the Sunkist meet on Wide World of Sports Saturday afternoon . . . The popular metropolitan mile relay has been discarded here. Georgetown ran poorly last week and withdres. Maryland has a dual meet at Navy Saturday afternoon and coach Frank Costello did not want his atheletes to run hard early in the season . . . Beaufort Brown has replaced Horace Tuitt, the defending champion and record holder, in the 600. Tuitt reported a case of flu.