See other engines in this family
Mercury Thriftpower (1964–1983) specs: 200 ci (3.3L) 6-cylinder, 3.68 x 3.126 in (93.5 x 79.4 mm) bore and stroke. Rated 87-120 hp, 1964–1983.
The Mercury Thriftpower (1964–1983) is oversquare — the 3.68" bore exceeds the 3.126" stroke by 17.7% — a layout that favors airflow and RPM over leverage at the crank. The 3.126" stroke does not reach 4,000 ft/min of mean piston speed until about 7,700 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 33.3 ci (546 cc).
It is one of 6 engines in the Thriftpower family, sitting between the 144 ci and 250 ci members. 17 factory variants share these dimensions, rated from 87 to 120 hp across 1964–1983.
| Displacement | 200 ci / 3.3 L |
|---|---|
| Bore | 3.68" |
| Stroke | 3.126" |
| Cylinders | 6 |
| Configuration | I6 |
| Compression ratio | 8.8–9.2:1 (published figures vary) |
| Bore/stroke ratio | 1.177 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Firing order | 1-5-3-6-2-4 |
| Advertised HP | 87–120 hp |
| Years | 1964–1983 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 1965 | gross | 120 @ 4400 | 190 lb-ft @ 2400 | 9.2:1 |
| 1966 | gross | 120 @ 4400 | 190 lb-ft @ 2400 | 9.2:1 |
| 1967 | T gross | 120 @ 4400 | 190 lb-ft @ 2400 | 9.2:1 |
| 1968 | gross | 115 * | — | 8.8:1 * |
Factory specification sheet. * Not yet cross-verified.
| Bore/stroke character | 1.177 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,126 ft/min — conservative for a street engine |
| Displacement per cylinder | 33.3 ci |
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 |
|---|---|---|
| 1964 | — | — |
| 1965 | 120 hp | — |
| 1966 | 120 hp | — |
| 1967 | 120 hp | — |
| 1968 | 115 hp | — |
| 1971 | 115 hp | — |
| 1972 | 91 hp | — |
| 1973 | — | — |
| 1974 | — | — |
| 1976 | — | — |
| 1977 | — | — |
| 1980 | — | — |
| 1981 | — | — |
| 1981 | 88 hp | — |
| 1982 | — | — |
| 1982 | 87 hp | — |
| 1983 | — | — |
7 factory vehicles, 1964–1983. Each year opens that model's engine table.