Jeep AMC I6 Engine Specs

Bore, stroke, displacement and compression for all 7 Jeep AMC I6 engines, compared side by side. Plus rod ratio and head specs where published.

At a glance

Displacement	232–258 ci
Cylinders	6
Bore	3.752–3.874"
Stroke	3.413–3.902"
Compression	8.3–8.8:1
Advertised power	100–190 hp
Years	1965–1978

Engines in this family

Engine	Displacement	Bore × Stroke	CR	HP
258	258 ci	3.752" × 3.9016"	8.3:1	112
6-258	258 ci	3.752" × 3.9016"	—	150
40 AMC I6 HO	242 ci	3.874" × 3.4134"	8.8:1	190
232	232 ci	3.752" × 3.5"	8.5:1	100
6-232	232 ci	3.752" × 3.5"	—	145
AMC 232 1-bbl	232 ci	3.752" × 3.5"	—	100
Hi-Torque 6	232 ci	3.752" × 3.5"	—	145

Factory cars with a AMC I6

• Jeep Gladiator: 1965, 145 hp; 1966, 145 hp; 1967, 145 hp; 1968, 145 hp; 1969, 145 hp; 1970, 145 hp; 1971, 145 hp
• Jeep Wagoneer: 1965, 145 hp; 1966, 145 hp; 1967, 145 hp; 1968, 145 hp; 1969, 145 hp; 1970, 145 hp
• International Scout: 1969, 145 hp; 1971, 145 hp; 1972, 150 hp
• Jeep CJ: 1972, 100 hp; 1973, 100 hp; 1974, 100 hp; 1975, 100 hp; 1976, 100 hp; 1977, 100 hp; 1978, 100 hp

What varies across the family

Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.

5 of 7 are oversquare — bore larger than stroke, which favours revs over low-end torque.

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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