Run Motorcraft SP-413 or Autolite 25 plugs gapped to 0.044" on the 5.0/5.8L Windsor. Torque to 15 ft-lb. Replace the wires at the same interval — old wires waste new plugs.
The Windsor V8 in every full-size Bronco uses a tapered-seat plug with no gasket. Stock gap from the factory is 0.044". Don't deviate unless you've switched ignition systems — running a 0.054" gap on a stock TFI coil burns out the cap and rotor faster than it gains you anything. Motorcraft SP-413 (platinum, ~25,000-mile interval) is the conservative choice. Autolite 25 (copper, ~15,000-mile interval) is the cheap, predictable, proven option that has been in millions of these engines.
Wires are where most people leave money on the table. A worn set of wires arcs to the valve covers under load and the engine stumbles, surges, or pings under wide-open throttle. If the wires have brittle boots, cracked insulation, or any green-blue corrosion at the boot end, replace the set when you do plugs. Motorcraft factory wires are fine for daily use; MSD or Taylor 8.5–9mm aftermarket wires are worth the upcharge if you wheel in deep water or thread an extension hose for high-water crossings.
The driver's-side rear plug (cylinder 7) is the one that costs you knuckle skin every time. The exhaust manifold and the firewall are both right there. Use a 5/8" spark-plug socket with a rubber retainer, an extension, and patience. Anti-seize is optional on Motorcraft plugs — the threads come plated — but on Autolites, a single dab of nickel anti-seize on the threads is good insurance. Never anti-seize the electrode end.
Pull and replace one wire at a time so you don't cross firing order (1-3-7-2-6-5-4-8 on the 302 and 351W). Run a little dielectric grease inside each boot. Crank the engine for two seconds with the coil wire disconnected before reconnecting to clear any oil that fell down the plug well — this is a 351W habit that prevents the first start from misfiring.
| Part | Vendor | Est. price |
|---|---|---|
| Motorcraft SP-413 spark plugs (set of 8) | Motorcraft | ~$32 |
| Autolite 25 copper spark plugs (set of 8) | Autolite | ~$18 |
| Motorcraft 9mm spark plug wires | Motorcraft | ~$65 |
| MSD 8.5mm Super Conductor wires (8-cyl, 90-degree) | MSD Ignition | ~$95 |
| Dielectric grease tube | Permatex | ~$4 |
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.