Classic Machines TractorsClassic Machines: The Allis-Chalmers HD-11 tractorContrafed PUblishingJuly 11, 2016November 25, 2019 by Contrafed PUblishingJuly 11, 2016November 25, 2019 Designed as a replacement for an earlier tractor, the Allis-Chalmers HD-11 was a very worthy successor and was in production for over 25 years. By...