Autolite AR 3933X racing spark plug. Cut-back ground electrode. Speed Karts, Charlotte, NC.
| Resistor | No |
|---|---|
| Center electrode | Copper core, nickel tip, short projection |
| Ground | Single, surface discharge, nickel core, steel tip |
| Pre-gap | 0.03 in |
| Thread | 14 mm |
| Reach | 22.352 mm |
| Seat | Flat |
| Heat range | 15 |
| Hex | 16 |
| Washer included | Yes |
| Terminal | Non-removable nut |
