| 1968 Firebird Speedometer Gear usage Chart | |||||||||||||
| Driven Gear Or Sleeve | Tire Size | Speedometer Adapter | |||||||||||
| Rear End Ratio | Part # | Teeth | Color | F70 X 14 | 195R X 14 | E70 X 14 | Model | Ratio | Part # | Color | Trans Code | Drive Gear Teeth | |
| 3.08 | 3870351 | 17 | PURPLE | X | X | X | FF | 7 | |||||
| 3.23 | 3860341 | 18 | BROWN | X | X | X | FH-FF | 7 | |||||
| 3.36 | 3860341 | 18 | BROWN | X | X | FH-FF | 7 | ||||||
| 3.55 | 3860342 | 19 | NATURAL | X | X | FH-FF | 7 | ||||||
| 3.55 | 3987920 | 20 | BLUE | X | FH | 7 | |||||||
| 3.90 | 9780522 | 18 | GREEN | X | X | FX | 6 | ||||||
| 4.33 | 3860329 | 20 | YELLOW | X | X | FX | 6 | ||||||
| Information supplied by George Pearson, taken from a Pontiac Parts Book | |||||||||||||