Allis Chalmers D-21
Oct 01, 2013
This Allis Chalmers D-21 owned by Henry Kellenberger of Jackson, Mich., was the first AC tractor to produce over 100 hp, the Heritage Iron 2013 Calendar reports:

It was built from 1963-69. This is the featured Heritage Iron 2013 Calendar tractor for October. To order the calendar, go to HeritageIron.com.