An improved model, the two-plow F-14, was produced beginning in 1938 and ending in 1939, when the Farmall letter series tractors were introduced.

The F-12 was a smaller, modernized version of the earlier Farmall Regular, developed from a prototype designated the F-10.

To reduce mechanical complexity and to improve transmission efficiency, the Regular's portal axle rear wheel arrangement was changed to a straight axle, with larger wheels to provide ground clearance.

This had the additional benefit of allowing a broader range of wheel adjustment to accommodate different row-crop row widths.

[1][2][3][5] The Farmall F-14 replaced the F-12 in 1938, with a 16 horsepower (12 kW) engine of the same displacement, running at higher RPMs, which allowed a two-plow rating.