See other engines in this family
Buick 1985 350 105HP specs: 350 ci (5.7L) 8-cylinder, 4.057 x 3.385 in (103 x 86 mm) bore and stroke, 22.5:1 compression. Rated 105 hp, 1985. OHV.
The Buick 1985 350 105HP 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 1.739 is in the range most production engines fall in. Each of the 8 cylinders displaces 43.8 ci (717 cc).
At 22.5:1 this is a compression-ignition engine: the ratio is the heat source that lights the fuel, not a knock limit to be managed.
It is one of 4 engines in the Buick 350ci family, all of them 350 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 350 ci / 5.7 L |
|---|---|
| Bore | 4.057" |
| Stroke | 3.385" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 22.5:1 |
| Rod length | 5.885" |
| Rod ratio | 1.739 |
| Bore/stroke ratio | 1.199 |
| Piston deck clearance | 0.046" |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | diesel |
| Advertised HP | 105 hp |
| Years | 1985 |
| 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 | 1.739 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 43.8 ci |
| Static compression | 22.5:1 — high enough that pump premium or better is normally required |
| Intake valve diameter | 1.88" |
|---|---|
| Exhaust valve diameter | 1.567" |
| Chamber volume | 60.58 cc |
| Rocker ratio | 1.6:1 |
| Lifter type | hydraulic |
Each link opens the calculator with this engine's specs already filled in.