You first should have a good idea of what your engine needs for cranking spark advance without kicking back – and set the handheld’s “Distr Base Timing” to that value. Keep in mind that this value is then your minimum spark advance allowed, and that the system cannot advance much more than 30 degrees from this value without causing some arcing under the distributor cap (depending on the rotor and cap dimensions). Start the engine (if it won’t start – be sure you’re getting spark and then move the distributor around to at least get it to start). Hold the RPMs above idle (e.g. 2500 RPMs). Watch the “Spark Advance” in the handheld and use your timing light to see timing move the distributor until they match each other. Lock down the distributor – you’re synched!