He was born in Missouri before his family moved to Vanport, Oregon, in 1943, where his father worked in a shipyard.
Shelton also became regular competitor in Can-Am from 1966 to 1974, scoring points only in the 1974 season driving a McLaren M8F.
[2] Outside of sportscars, Shelton had a brief single-seater career driving in Formula 5000 cars, racing a Gurney Eagle during the 1971 SCCA L&M Continental 5000 Championship.
He also served as a co-founder of SCCA's Oregon Region and held a competition license with the organization for over 60 years.
[6] Outside of racing, Shelton owned a collector car dealership called "Monte's Motors", where he specialized in British automobiles.