Chevrolet 350ci 12.5:1 Specs: 4.065 x 3.37 in, 530-630 hp

See other engines in this family

Chevrolet 350ci specs: 350 ci (5.7L) 8-cylinder, 4.065 x 3.37 in (103.3 x 85.6 mm) bore and stroke, 12.5:1 compression. Rated 530-630 hp, 2014–2023. OHV.

The Chevrolet 350ci is oversquare — the 4.065" bore exceeds the 3.37" stroke by 20.6% — a layout that favors airflow and RPM over leverage at the crank. The 3.37" stroke does not reach 4,000 ft/min of mean piston speed until about 7,100 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. A rod ratio of 1.884 is long by production standards — less side-load on the cylinder wall and gentler piston acceleration around TDC, the geometry that tolerates high RPM. Each of the 8 cylinders displaces 43.8 ci (717 cc).

12.5:1 on iron heads is high for a production gasoline engine; running a ratio like that on pump fuel depends on chamber design and fuel delivery rather than the number alone.

It is one of 34 engines in the Chevrolet 350ci family, all of them 350 ci — the differences between them are in compression, heads and rating, not displacement. 14 factory variants share these dimensions, rated from 530 to 630 hp across 2014–2023.

Dimensions

Displacement350 ci / 5.7 L
Bore4.065"
Stroke3.37"
Cylinders8
ConfigurationV8
Compression ratio12.5:1
Rod length6.35"
Rod ratio1.884
Bore/stroke ratio1.206
Piston deck clearance0.01"

Construction

Block materialcast iron
Head materialcast iron
ValvetrainOHV
Fuel typegas
Advertised HP530–630 hp
Years2014–2023

What these numbers mean

Bore/stroke character1.206 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves
Mean piston speed at 6,000 RPM3,370 ft/min — conservative for a street engine
Rod ratio1.884 — long — less side loading on the cylinder wall, favours high RPM
Displacement per cylinder43.8 ci
Static compression12.5:1 — high enough that pump premium or better is normally required

Cylinder head

Intake valve diameter2.205"
Exhaust valve diameter1.615"

Run the numbers for this engine

Each link opens the calculator with this engine's specs already filled in.

Variants sharing these dimensions (14)

These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.

YearAdvertised HPCode
2014530 hp—
2015530 hp—
2017580 hp—
2017590 hp—
2018580 hp—
2018590 hp—
2019600 hp—
2019630 hp—
2020600 hp—
2020630 hp—
2022600 hp—
2022630 hp—
2023600 hp—
2023630 hp—

Similar engines

← All Chevrolet 350ci engines