Help send a strong spark to every cylinder using the MSD IGNITION spark plug wire set (P/N 31339), a custom 8.5mm set cut to exact specifications for Ford engines with HEI boots. It's a direct-fit replacement for the listed applications, including the 1977-1981 Ford F-150 5.8L / 6.6L, 1977-1982 Ford F-250 5.8L / 6.6L and 1978-1981 Ford Bronco 5.8L / 6.6L, and many more Ford, Lincoln, and Mercury V8-5.8L and V8-6.6L models — see the "Vehicles it fits" section for the full list.
Pre-cut for a custom, bolt-on fit. Country of origin: Mexico.
Is this the right spark plug wire set for a 1977-1981 Ford F-150 5.8L / 6.6L?
Yes — it's listed as a direct fit for the 1977-1981 Ford F-150 with the V8-5.8L or V8-6.6L engine. Check the "Vehicles it fits" section to confirm your exact year and engine.
What size are these spark plug wires?
They are 8.5mm MSD Super Conductor wires with Multi-Angle HEI boots and red sleeves, pre-cut to exact specifications for the listed applications.
How do these wires reduce electronic interference?
The conductor is wound tightly around a ferro-magnetic impregnated center core, which acts as a choke to help keep electromagnetic interference (EMI) inside the wire and away from other electronics.
What makes the resistance so low?
A copper alloy conductor wound around a special center core provides very low resistance — only about 40-50 ohms per 12 inches — so less spark energy is lost reaching the plug.
What are Dual Crimp terminals?
As the name implies, each terminal uses two separate crimps: one that grips the sleeve of the wire and another that grasps the conductor for a secure connection.
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WARNING: These products can expose you to chemicals including lead and phthalates, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
