If we were to compile a list of Detroit’s Most Wanted and started filling in the blanks in the ‘Muscle Cars’ section, one certain General Motors Division wouldn’t have much trouble sleeping at night.

Anson Renshaw, a real-estate valuation officer living in Mesa, Ariz., on his 1966 Buick Wildcat, as told to A.J. Baime. When I was about 5 years old, I remember my grandma picking me up from the ...