At one time, the Allis-Chalmers HD-41 was the world’s largest bulldozer. In this video, members of the Lowcountry Antique Tractor and Engine Association operate a 1972 HD-41 named “Big Roy.” The dozer was saved by Roy Ashley and again by Frank Burke of Walterboro, South Carolina, who named the dozer after his friend Roy Ashley after he passed away. Burke donated the dozer to the tractor club. The club brings out the HD-41 each April and October for its antique tractor pulls on its grounds in Ada