The gas versions use different engines (159ci = 530, 188ci = 630), while the diesels used the same engine. Beyond the engine, there are a number of subtle differences and a couple that are relatively obvious.
The 630 general purpose tractors were equipped with 36" rear tires, while the 530s were equipped with 28" rear tires. This difference resulted in some additional, subtle differences between the two tractors.
- The fenders on the 630 look similar to the 530 version, but they have an extension welded on the lower portion to account for the larger tires/wheels.
- The 630 also has longer lift arms on the eagle hitch.
- The 630 has taller front spindles (both narrow and wide front assemblies)
There are some additional differences, but the ones mentioned are the most obvious. - Joe