 Complete the following phrase:  Both Iso Rivolta and Marlboro left before the 1974 season, leaving Williams with ficial problems. The two IR chassis were retained, now re-designated the FW after Frank Williams, but initially only a single car was entered for Arturo Merzario, who had replaced Ganley as the teams number one driver. There was an early-season boost as Merzario placed sixth in the third race of the season in 