The ignition coil is the very heart of the fire for older Corvettes, and it’s one of those parts that can fail totally without warning, or give you subtle hints of its imminent demise. The latter was the case with the coil on my ’67 big-block coupe with transistorized ignition. The first symptoms were a noticeable loss of pep in the lower RPM range, "breaking up" in the higher rev range, and some serious post-ignition, more widely known as "dieseling" when the ignition is shut off. A new coil was ordered from Zip Products, and here’s what it took to install it.