A little more accurate procedure than just pulling plug wires is called a "power balance test". It takes an accurate tachometer and a vacuum gauge. Set the speed to a fast idle, maybe 1000-1500 RPM and monitor the manifold vacuum. (NOT distributor vacuum- - - -tap into the main plenum under the carburetor. Each time you disconnect a plug wire, record the RPM drop and the vacuum change. In some rare instances involving burned intake valves or a sticky EGR valve, the RPM might actually speed up when a wire is disconnected. Usually, disabling a good cylinder will cause a drop in RPM and vacuum, while disconnecting a low-powered or dead cylinder will not have much of an effect. If you also happen to have an exhaust gas analyzer connected, you'll see a rise in unburned hydrocarbons when a good cylinder is disabled.
Jerry
