421 Compression Calculator
| Bore: (diameter) | |
| Stroke: | |
| Cylinder Head Volume: | |
| Effective Dome Volume:Butler Ross Flat Top 8cc | |
| Deck Clearance: | |
| Compressed Gasket Thickness: .040 is standard thickness | |
| Number of Cylinders: | |
| Compression Ratio : | |
| Total Displacement (in.3) : | |
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| 421 Block | Stroke | |||||
| Bore | 3.75 | 4.00 | 4.21 | 4.25 | 4.50 | |
| Stock | 4.093 | 421 | 443 | 447 | 474 | |
| +.030 | 4.123 | 427 | 450 | 454 | 481 | |
| +.035 | 4.128 | 428 | 451 | 455 | 482 | |
| +.040 | 4.133 | 429 | 452 | 456 | 483 | |
| +.060 | 4.153 | 433 | 456 | 461 | 488 | |
| +.065 | 4.158 | 435 | 457 | 462 | 489 | |