This was one of the smallest production four-cylinder automobile engines in history, only beaten by Honda's 356 cc (21.7 cu in) inline-four unit used in the T360 truck.
Mazda's tiny OHV was the only four-cylinder in the class in the 1960s, but was outperformed by 2-stroke and I3 powerplants from other companies.
[4] The 1.0 L (987 cc) PB engine, a separate development, used a square 68 mm (2.68 in) bore and stroke.
One of the more-popular variants of this family was the 1.2 L (1,169 cc) TB unit found in the Familia/1200.
The UA (and the similar UB, for use in three-wheeled trucks) is a 1484 cc water-cooled overhead valve inline-four engine.
The B1500's output remained the same but for the second generation B1500 an improved engine cylinder head and valves and a downdraft carburetor increased the maximum horsepower to 72 PS (53 kW) at 5200 rpm and a maximum torque of 12.0 kg⋅m (118 N⋅m; 87 lbf⋅ft) at 3400 rpm.