Here is a little more info...just not on that specific machine, which I know nothing about, just saw it on craigs list...
the "County Super 4", Model 654. The name County comes from the County Commercial Cars Ltd in Fleet, Hants, UK. This company used to purchase Ford four cylinder power trains on skids and then added their own four wheel drive front axle with equal size front and rear wheels. They were sold in North America by some Ford tractor dealers from approximately 1955 to 1980. A few ended up in the US; most of them went to Western Canada where they were popular with the loggers.
They started this series with the Model 654, and then expanded or upgraded with model designations such as 754, 1004, 1164, 1184, and others. The 654 was built from November 1964 to June 1968, then replaced by the Model 754 built from May 1968 through November 1975. The smaller models used 5000 and 7000 four cylinder Basildon tractor engines. The 754 and 1184 used a Basildon six cylinder (8000TW) engine. The larger ones used Ford Dorset (2700 range) industrial diesel engines.
They were durable, reliable tractors, with several owners in the UK still speaking highly of them. County, during the manufacturing process, would disassemble the transmissions and rear axles, and install bearings made to a higher specifications than the original ball bearings. In some cases they would even install their own final ring and pinion gears.
On the down side, they had too large of a turning circle and they were a bear to horse around because of the weak power steering. In the UK, they were first promoted for plowing. However farmers who owned both a County Super and a Super Major (for example) felt they both had the same pulling power, and so (except for large acreage) they favored the Major for its live PTO and ease of handing. In the UK, most of the Countys ended up in forestry service just like in Canada. Another negative: with all this additional mechanism, replacing clutch, or even brakes, was a pain.
Repair parts have always been hard to find, specially the uniquely County items like hub gears and castings. Now that the company is out of business, this can be an even greater problem. The best source is a Scotsman, Jas Wilson, who has taken a liking to refurbishing the things. His link is
http://freespace.virgin.net/jasp.wilson/index.htm. As for the rest of the power train, parts were mostly available through the regular Ford dealerships.