OER Parts offers a wide selection of Coils for your 1978 Mercury Cougar. OER Parts offers 1978 Mercury Cougar OE Quality Ignition Coil, 1978 Mercury Cougar Replacement Ignition Coil Premium Quality, 1978 Mercury Cougar HEI Ignition Coils, 1978 Mercury Cougar Chrome Ignition Coils, 1978 Mercury Cougar Zinc Plated Ignition Coil Bracket, 1978 Mercury Cougar Ignition Coil Resistor, and 1978 Mercury Cougar Chrome Ignition Coil Bracket & Chrome Coil Cover.