Chevrolet LF9 specs: 350 ci (5.7L) 8-cylinder, 4.057 x 3.385 in (103 x 86 mm) bore and stroke. Rated 105 hp, 1982–1983. Used in the Oldsmobile 98. OHV.
The Chevrolet 350ci (LF9) is oversquare — the 4.057" bore exceeds the 3.385" stroke by 19.9% — a layout that favors airflow and RPM over leverage at the crank. The 3.385" 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 1.684 is in the range most production engines fall in. Each of the 8 cylinders displaces 43.8 ci (717 cc).
It is one of 37 engines in the Chevrolet 350ci family, all of them 350 ci — the differences between them are in compression, heads and rating, not displacement. 2 factory variants share these dimensions, rated at 105 hp across 1982–1983.
Dimensions
Displacement
350 ci / 5.7 L
Bore
4.057"
Stroke
3.385"
Cylinders
8
Configuration
V8
Compression ratio
22.1–22.5:1 (published figures vary)
Rod length
5.7"
Rod ratio
1.684
Bore/stroke ratio
1.199
Construction
Block material
cast iron
Head material
cast iron
Valvetrain
OHV
Fuel type
diesel
Firing order
1-8-4-3-6-5-7-2
Advertised HP
105 hp
Years
1982–1983
Factory ratings by year
Year
Version
HP @ rpm
Torque @ rpm
Comp.
1982
LF9 net
105 @ 3200
200 lb-ft @ 1600
22.5:1
1983
LF9 net
105 @ 3200
200 lb-ft @ 1600
22.1:1
Factory specification sheet.
What these numbers mean
Bore/stroke character
1.199 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves
Mean piston speed at 6,000 RPM
3,385 ft/min — conservative for a street engine
Rod ratio
1.684 — moderate — the range most production V8s fall in
Displacement per cylinder
43.8 ci
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