Chevrolet 409ci Engine Specs

Bore, stroke, displacement and compression for all 7 Chevrolet 409ci engines, compared side by side. Plus rod ratio and head specs where published.

At a glance

Displacement	409 ci
Cylinders	8
Bore	4.125–4.313"
Stroke	3.500–3.825"
Compression	10.0–11.0:1
Advertised power	340–450 hp
Years	1961–2017
Cylinder head data	3 of 7 engines

Engines in this family

Engine	Displacement	Bore × Stroke	CR	HP
Chevrolet 409ci · 4.125" × 3.825"	409 ci	4.125" × 3.825"	—	450
RPO 580	409 ci	4.313" × 3.5"	—	360–380
RPO 587	409 ci	4.313" × 3.5"	—	409
L31	409 ci	4.313" × 3.5"	—	400
L80	409 ci	4.313" × 3.5"	—	425
Chevrolet 409ci · 4.313" × 3.5" · 10:1	409 ci	4.313" × 3.5"	10:1	340
Chevrolet 409ci · 4.313" × 3.5" · 11:1	409 ci	4.313" × 3.5"	11:1	400

Factory cars with a Chevrolet 409ci

• Chevrolet Bel Air: 1961, RPO 580, 360 hp; 1962, RPO 580, 380 hp; 1962, RPO 587, 409 hp; 1963, L33, 340 hp; 1963, L31, 400 hp; 1963, L80, 425 hp; 1964, L33, 340 hp; 1964, L31, 400 hp; 1964, L80, 425 hp; 1965, L33, 340 hp; 1965, L31, 400 hp
• Chevrolet Impala: 1961, RPO 580, 360 hp; 1962, RPO 580, 380 hp; 1962, RPO 587, 409 hp; 1963, L33, 340 hp; 1963, L31, 400 hp; 1963, L80, 425 hp; 1964, L33, 340 hp; 1964, L31, 400 hp; 1964, L80, 425 hp; 1965, L33, 340 hp; 1965, L31, 400 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.

All 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.

← All Chevrolet engines