GMC 427 Specs
GMC 427 engine specs: 427 ci (7L), 8-cylinder, 4.25" bore x 3.6402" stroke, 11:1 compression.
Dimensions
| Displacement | 427 ci / 7 L |
|---|
| Bore | 4.25" |
|---|
| Stroke | 3.6402" |
|---|
| Cylinders | 8 |
|---|
| Compression ratio | 11:1 |
|---|
| Bore/stroke ratio | 1.168 |
|---|
Construction
| Block material | cast iron |
|---|
| Head material | cast iron |
|---|
| Valvetrain | OHV |
|---|
| Fuel type | gas |
|---|
| Advertised HP | 335 hp |
|---|
What these numbers mean
| Bore/stroke character | 1.168 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|
| Mean piston speed at 6,000 RPM | 3,640 ft/min — in the range typical of performance street engines |
|---|
| Displacement per cylinder | 53.4 ci |
|---|
| Static compression | 11:1 — high enough that pump premium or better is normally required |
|---|
Run the numbers for this engine
Each link opens the calculator with this engine's specs already filled in.
Vehicles (2)
- GMC C/K Series
- GMC Medium Duty Trucks
Similar engines
← All Big Block Chevy engines