How do you find TDC for optispark?

To find the Top Dead Center (TDC) for an OptiSpark ignition system, first, remove the spark plugs to make it easier to turn the engine. Use a long, thin tool like a screwdriver or a dial gauge in the spark plug hole to feel for the piston at its highest point. Rotate the engine slowly by hand until the piston reaches its peak, then confirm TDC by aligning the timing mark on the harmonic balancer with the TDC mark on the timing cover. Finally, ensure the distributor rotor points to the correct position in relation to the reference mark for the OptiSpark system.