OER Parts offers a wide selection of Plugs & Wires for your 1977 GMC C15. OER Parts offers 1977 GMC C15 Universal Spark Plug Wires, 1977 GMC C15 OEM Style Spark Plug Wires, 1977 GMC C15 Date Coded Spark Plug Wire Set, 1977 GMC C15 Non-Dated Spark Plug Wire Set, 1977 GMC C15 6 Cylinder Spark Plug Wire Set, 1977 GMC C15 8 Cylinder Spark Plug Wire Set , 1977 GMC C15 Spark Plug Boot, 1977 GMC C15 Spark Plug Wire Puller, Spark Plug Gapper, 1977 GMC C15 Spark Plug Hole Thread Chaser, Accel Shorty Plugs, and1977 GMC C15 E3 Spark Plugs.