To remove the distributor, first detach the cable from the negative battery terminal and any clamps and electrical connectors on the distributor, marking the wires and hoses for reinstallation. Look for a raised number or letter on the distributor cap to identify the number one cylinder spark plug wire terminal; if absent, trace the wire from the number one spark plug to the cap. Remove the distributor cap and turn the engine until the rotor points toward the number one spark plug terminal. Make a mark on the distributor base directly below the rotor tip and in line with it, ensuring to mark both the distributor base and the cylinder head for correct reinstallation. Unplug the ICM wires, then remove the distributor hold-down bolt(s) and pull out the distributor. For installation, if the crankshaft has moved, reposition the number one piston at TDC by feeling for compression pressure at the number one plug hole while turning the crankshaft, aligning the ignition timing zero mark with the pointer. Install a new O-ring on the distributor housing, then insert the distributor into the cylinder head in the same orientation as when it was removed, ensuring the lugs and grooves align to prevent incorrect installation. Recheck the alignment marks between the distributor base and the cylinder head, and ensure the rotor aligns with the previously made mark. Loosely install the hold-down bolt(s), then complete the installation by reversing the removal steps, checking the ignition timing, and securely tightening the distributor hold-down bolt(s).