Ignition · Engine and Clutch
| System | Engine and Clutch |
| Subsystem | Ignition |
| Assembly | Spark Plugs |
| Thread | M14x1.25 |
| Years | 1972–1981 |
| Vehicles | 911SC, 911T/E/S |
| Confidence | Cross Referenced |
Source: Porsche 911 Workshop Manual, Section 0.2-5/2 (Tightening Torques for Engine) and Section 9 (Electrical System), page 938 (Ignition System - Spark Plugs)