Passwater started racing after the war and was active in the 1950s and 1960s. He won the fifth race of the 1953NASCAR Grand National Series season at Charlotte Speedway in his 1953 Oldsmobile. He won the race after most of the top contenders either fell out of the race or had to make a late pit stop at the 3/4 mile long dirt track. The race saw a then-record six drivers take the lead with 18 lead changes. He led three laps in his NASCAR career, all in this race at Charlotte. One of Passwater's Oldsmobiles is in a museum in Lansing, Michigan. He retired because car owner Frank Arford had died in a crash in Langhorne, PA while attempting to qualify for the race. Passwater returned home without a ride. He campaigned a self-owned Olds for his last race in the '53 Southern 500, finishing ninth. He raced in a USAC Stock Car during the 1960s.