Police said yesterday they are looking for two suspects in the fatal shooting of a Woodlawn man as he was driving his truck on U.S. Rte. 1 in Fairfax County Dec. 2.

After interviewing a number of witnesses to the shooting of Kevin McGann, a 21-year-old electrician, county police said they are looking for two teen-agers who, on the night of the shooting, were riding in a dark red or brown 1970 Chevy Nova or Plymouth Duster with a slightly raised rear axle.

According to witnesses, police said, McGann was driving north on Rte. 1 near Woodlawn Stables when he was cut off by a car that was trying to enter the highway.

Witnesses said McGann then raced his pickup past the car, crossing over a double line into the southbound lane to get in front of the auto. In turn, the car caught up to McGann's truck and one of two teen-agers inside fired a shot from a rifle. The bullet shattered the truck's rear window and struck McGann in the head.

The truck swerved across the southbound lanes and slammed into a tree on the 8700 block of Rte. 1. McGann was pronounced dead on the scene, police said.