Jacky Ickx, a 36-year-old Belgian, and Derek Bell, a 40-year-old Briton, led Porsche to a 1-2-3 sweep in the 50th Le Mans 24 hours road race today.

Ickx, out of retirement for this event, won for a record sixth time, and Bell won his third Le Mans. It also was the seventh victory for Porsche, which took the top three places in 1970 and the top four in 1979.

The three factory-entered turbocharged 956 coupes, built to this year's new World Endurance Championship rules, led for all but four of the 24 hours. Thousands of the estimated crowd of 125,000 spilled onto the track and prevented the drivers from completing their final lap.

The second car was driven by Australian Vern Schuppan--who suffered cramps from dehydration during the race, run in hot, dry weather--and West German Jochen Mass.

Americans Hurley Haywood and Al Holbert, with Porsche works driver Jurgen Barth, crewed the third car. They led for four hours Saturday before being delayed by a wheel bearing failure and by a door blowing off at high speed.

Ickx said, "We had no mechanical problems at all with the car," but he was lucky when a tire blew only yards before the pit road and not out around the 8.4-mile track.

He and Bell officially covered 3,044 miles in the 24 hours at an average speed of 126.839 mph.

The Porsche sweep was completed with fourth and fifth places for privately entered 935 coupes. British MSA racers John Fitzpatrick and David Hobbs were fourth in a car running for hours on five of six cylinders, ahead of the French crew of Dany Snobeck, Francois Servanin and Rene Metge in a similar car. A Belgian-entered 936 had been fourth but broke down with little more than an hour to go.

In the hour before the race started, the Mirage-Ford of former world champion Mario Andretti and his son Michael, 19, of Nazareth, Pa., was disqualified for a technical infringement. The team admitted a mistake.