John Deere Spark Plug Chart
| Year/s | Model | Original (champion) | NGK Cross Ref |
| 1972-73 | 400/500/60 | L81 | B7HS |
| 1973 | JDX4 | N2 | B9ES |
| 1973 | JDX8 | L78 | B7HS or B8HS |
| 1974 | 300 | RN3 | BR8ES |
| 1974 | 400/500/600 | RN2 | BR9ES |
| 1974 | JDX4S/JDX6/JDX8 | RN2 | BR9ES |
| 1974 | 295/S | N19-V | BUE |
| Year/s | Model | Original (champion) | NGK Cross Ref |
| 1972-73 | 400/500/60 | L81 | B7HS |
| 1973 | JDX4 | N2 | B9ES |
| 1973 | JDX8 | L78 | B7HS or B8HS |
| 1974 | 300 | RN3 | BR8ES |
| 1974 | 400/500/600 | RN2 | BR9ES |
| 1974 | JDX4S/JDX6/JDX8 | RN2 | BR9ES |
| 1974 | 295/S | N19-V | BUE |