Wiring, Plug Set, GM 4cyl with Digital Ignition: Spark Plug Wire Set Part # 18-8811-1 GM 4cyl with Digital Ignition Conventional Mag Force Spark Plug Wire Set,p remium Marine Wire Leads, Magnetic Suppression Kevlar Core, Durable stainless steel wound conductor for maximun life, horsepower and engine performance, Superior RFI suppression for the most sensitive electronic systems, Corrosion resistant stainless steel spark plug and distributor terminals for maximum conductivity, OEM style boots provide a sealed barrier against heat, dirt and moisture replaces: OMC 503748 replaces: Mercury Marine 84-813720A13 replaces: OMC 503749