Austin-Healey 178ci Specs: 83.3 x 88.9 mm

Austin-Healey 178ci specs: 83.3 x 88.9 mm (3.2811 x 3.5000 in) bore and stroke, shared by all 3 versions. Displacement, compression and factory ratings.

At a glance

Displacement	178 ci
Cylinders	6
Bore	3.281"
Stroke	3.500"
Compression	9.0:1
Advertised power	124–150 hp
Years	1959–1967

Engines in this family

Engine	Displacement	Bore × Stroke	CR	HP
29D	178 ci	3.2811" × 3.5"	9.03:1	124
29E / 29F	178 ci	3.2811" × 3.5"	9.03:1	—
29K	178 ci	3.2811" × 3.5"	—	150

Factory cars with a Austin-Healey 178ci

• Austin-Healey Austin-Healey 100 / 3000: 1959, 124 hp; 1960, 124 hp; 1961; 1961, 124 hp; 1962; 1963; 1964, 150 hp; 1965, 150 hp; 1966, 150 hp; 1967, 150 hp

What varies across the family

All are undersquare — stroke larger than bore, favouring torque low in the range.

Each engine page carries rod ratio, mean piston speed, bore/stroke character and cylinder head specs where published, and links into the calculators with its dimensions already filled in.

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