The single highest-value maintenance task on a carbureted early Bronco is replacing the points with a Pertronix Ignitor. $90, 45 minutes, and you've eliminated the most failure-prone component in the entire ignition system.
**Timing specs:**
**Tune-up procedure:**
1. **Plugs:** Gap to 0.035" for points ignition, 0.044" for Pertronix or MSD. Use Motorcraft SP432 (302/351W) or equivalent copper core. Install with anti-seize on the threads.
2. **Points (if still using them):** Set gap to 0.017" with feeler gauge, or set dwell to 26–30° with a dwell meter. If you're doing this, seriously consider the Pertronix swap instead.
3. **Cap and rotor:** Replace every 30,000 miles or if carbon tracking is visible on the cap interior.
4. **Plug wires:** Inspect for cracks, especially near the boots. Resistance test each wire (should be under 10,000 ohms/foot). Gates or MSD wires are reliable aftermarket options.
5. **Timing:** Set with a timing light, engine at operating temp, vacuum advance disconnected and plugged.
6. **Carburetor:** Check float level (Autolite 2100: 7/16" from gasket surface to top of float). Check for fuel bowl leaks at the float valve seat. Idle mixture screws: start at 1.5 turns out from lightly seated and adjust for highest idle vacuum.
**Vacuum advance check:** A working vacuum advance retards timing when you release the throttle, advancing it under load. Disconnect the vacuum line at idle — if timing jumps 6–12°, the advance canister is working. If it doesn't move, replace the advance canister ($12).
| Part | Vendor | Est. price |
|---|---|---|
| Pertronix Ignitor I (points replacement) | Pertronix | ~$90 |
| Motorcraft SP432 plugs (set of 8) | Motorcraft | ~$24 |
| Distributor cap and rotor set | Standard Motor Products | ~$28 |
| Autolite 2100 rebuild kit | Autolite | ~$30 |
| Gates ignition wires (set of 8) | Gates | ~$45 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.