Checking for spark is pretty easy to do. You simply pull a spark plug from the engine (or use a spare plug if you have one in your parts box, snap one of the plug wires onto it and make sure the shank of the plug is grounded against the engine block (do not hold onto the spark with your bare hands unless you want to get a really nasty jolt - spark plug boot pulling pliers or other insulated-handle pliers are a good thing to use for this purpose). Have someone crank the engine and observe the center electrode of the plug - if there's sufficient voltage reaching the plug, you should see a bright blue spark jump across the gap of the electrode every time that cylinder fires. If you see no spark, the coil is a good thing to suspect next. You'll need a digital multimeter to check the resistance levels of your coil. The side terminals of the coil are marked positive (+) and negative (-) and these are where you can measure the resistance of the primary windings. Set the multimeter to the 200-ohm setting and attach the meter's leads corresponding to the terminal markings, red being positive and black being negative. The normal primary reading for 12V (1956 and later) Corvettes on the primary side is 1.6, although a range of 1.5 to 1.7 is acceptable. Next, you'll want to measure the resistance of the secondary coil, and this is the real business-end of the spark-producer. Switch the meter's resistance range to the 20K-ohm setting and attach the negative (black) meter lead to the center terminal of the coil. The reading here should be 11.00 or better, with 13.49 being about normal. If your coil reads under 11.00, then chances are pretty good that this is the reason you're not getting any spark or a very weak one. Replace the coil with a good quality new one (e.g., GM Delco), but it’s VERY important that you replace the coil with the correct one. For example, as noted earlier, a ‘67 Big Block with transistorized ignition requires a special coil; a standard coil will not work with transistorized ignition, and vice versa. Replacing the coil isn’t rocket science, but it helps if you make diagrams or take digital photos along the way to avoid mistakes and confusion when it’s time to put things back together. So here we’re going to show you step-by-step on how to troubleshoot and then replace the coil on a ‘63 Midyear coupe