Model A historian Steve Plucker, using Ford company records, calculates that 4,830,806 production engines were built between October 1927 and November 1931.

During that time, the Model A and AA engine cylinder block (part number A-6010), went through various external and internal changes.

To allow better performance at low altitudes, and in cold weather, the fuel/air mixture ratio is controlled by a manual choke and "Gas Adjusting Valve" (GAV).

The resulting gas was routed to the engine's intake manifold, via a duct and special induction system.

[28][29][30] The electrical system supporting the engine typically consisted of a 6-volt battery, a 6-volt DC generator (driven by a belt connected to the crankshaft pulley), starter, lights, ammeter, and ignition system (ignition coil, distributor, spark plugs) with connecting wires.

The vast quantities of Ford Model A engines produced, during a short time, flooded the market.

[12] Tens of thousands of the original design remain active even in the 21st Century – particularly powering Ford Model A cars preserved as recreational antiques.

[36][37] These controls were mounted on the floor (accelerator and starter pedals), or steering column (spark advance and manual throttle), or on (or immediately below) the dashboard.

[36][37] Reportedly, the State of Pennsylvania required the gas shutoff valve to be mounted inside the engine compartment, instead.

[41] Aftermarket parts and modifications became widely available,[1][39][40][42] enabling improvements for racing – with some modified engines reaching compression ratios of 12:1, producing 250 horsepower.

The Ford Model A and B engines dominated American auto racing until World War II[41][43][44][13] Some racing is still done with Ford Model A engines,[43][45][46][47] and high-performance aftermarket modifications are available to increase performance, with some achieving 110 horsepower, at compression ratios of up to 6.5-to-1.

Farmers were expected to cut costs on kits by buying used parts to complete them, but the company recommended a Ford HD truck radiator and four-blade fan.

[50] Some other manufacturers' tractors, such as Thrifty Tractor (starting in 1930, and listed in the Sears spring and fall catalogs from 1932 to 1941[51]), were sold by Sears, Montgomery Ward, and others as kits, without the engine – though designed to use the Ford Model A engine, which buyers were expected to find on their own.

[6][52][53][54] Evolving from the kits they sold, Sears, Roebuck & Company's Economy (or "New Economy") tractors, first built in 1938 by Peru Plow Works, were complete tractors, with a rebuilt Ford Model A engine included, along with self-starter, governor, special carburetor, air cleaner and oil filter.

[6] During the economic hardships of the Great Depression, which financially devastated many farmers,[58][59][60][61] these various low-cost tractors – powered by the affordable, plentiful Ford Model A engine – provided a comparatively inexpensive, minimal tractor for essential, basic agricultural work.

However, production ended in 1948 when Ford became a competitor, manufacturing tractors of its own, and stopped selling components to Speedex.

In 1932, at Fort Bragg, North Carolina, the 17th Field Artillery Ford Motorized Battery used these vehicles to transport 75mm guns, supplies, and support and command personnel.

Previously, the Army had relied on horses and mules to transport light artillery; this experiment changed that.

[9][68][69] Examples include the wheeled FAI & FAI-M (Soviet Union) armored cars,[68] and the tracked TKD[69] and TK-3[9] "tankettes" (Poland) (lightweight, fast scout tanks – 690 in all – the short-lived bulk of Polish armor at the start of World War II).

[70][71][72] In the 1930s, during the Great Depression, aviation enthusiasts were frustrated by the cost of acquiring or building an airplane, largely due to the most expensive part: the engine.

The Model A engine, available cheaply,[75][76] and fairly light while providing 40 horsepower[13][75] – and designed for operation at low-RPM speeds ideal for propellers[13] – proved adaptable to some single-seat or two-seat aircraft.

[26] In November, 1933, the U.S. Bureau of Air Commerce started a program to make personal aircraft as common as medium-priced automobiles.

Some modified the cylinders to allow for a second spark plug (to accommodate dual ignition systems for redundant safety and enhanced performance).

Though radiator placements varied, it was most often placed immediately above the engine, significantly blocking the pilot's forward view.

[84] In another case, a Ford Model A engine was used to drive a suction pump used to dredge the bottoms of bodies of water for gold mining.

[85] At another site, another Model A engine was used to reverse a dredge's bucket line when it scooped a rock too big for the machine.

[56] In addition to the Ford Model A engine's use in tractors, its industrial variant also powered the popular Gleaner-Baldwin farm combines.

The combine's Model A engine was mounted on a frame fitted for the radiator, and was coupled to a power take-off unit.

It called for powering the boat with a Ford Model A engine – though it was not ideal, owing to weight, temperament, and carburetors that sometimes leaked fuel.

[103][101][104][13] Several organizations, publications and websites support owners of vehicles that use the Model A engine,[98] including antique auto,[105][106] truck,[107] and tractor[7][64] clubs, as well as experimental aircraft associations.