Photo credit: TractorZoom This Massey-Harris Pacemaker vineyard tractor is extraordinarily rare...but what’s up with the cowbell on the front? The Massey-Harris Pacemaker isn’t super-rare. They’re not super-common, either. There were about 3,000 built over two(ish) years. They were a great little Depression-era farm tractor. They have an interesting history, though. The Pacemaker was a direct descendent of a pretty groundbreaking tractor with ties to the Case family. Sort of... Wallis Tractor Co. The Pacemaker’s bloodline began with a company called Wallis Tractor Co. Henry Wallis was Jerome Increase Case’s son-in-law, and he started the company in 1912. Wallis Tractor Company pioneered the uniframe, a revolutionary concept in tractor-building.