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Buick LT7 specs: 262 ci (4.3L) 6-cylinder, 4.057 x 3.385 in (103 x 86 mm) bore and stroke, 22.8:1 compression. Rated 85 hp, 1982–1983.
The Buick 262ci (LT7) 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 6 cylinders displaces 43.7 ci (716 cc).
At 22.8:1 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 3 engines in the Buick 262ci family, all of them 262 ci — the differences between them are in compression, heads and rating, not displacement. 2 factory variants share these dimensions, rated at 85 hp across 1982–1983.
| Displacement | 262 ci / 4.3 L |
|---|---|
| Bore | 4.057" |
| Stroke | 3.385" |
| Cylinders | 6 |
| Configuration | V6 |
| Compression ratio | 22.8:1 |
| Rod length | 5.885" |
| Rod ratio | 1.739 |
| Bore/stroke ratio | 1.199 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | diesel |
| Advertised HP | 85 hp |
| Years | 1982–1983 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 1983 | LT7 net | 85 @ 3600 | 165 lb-ft @ 1600 | 22.8:1 |
Factory specification sheet.
| 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 | 43.7 ci |
| Static compression | 22.8:1 — high enough that pump premium or better is normally required |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 1982 | 85 hp | LT7 |
| 1983 | 85 hp | LT7 |
6 factory vehicles, 1982–1985. Each year opens that model's engine table.