How do you know if a Jeep 4.2L engine is at top dead center with the distributor?

To determine if a Jeep 4.2L engine is at top dead center (TDC), first remove the spark plug from cylinder number one. Rotate the engine using a socket on the crankshaft until you feel air escaping from the spark plug hole, indicating the piston is approaching TDC on the compression stroke. Next, align the timing mark on the harmonic balancer with the TDC mark on the timing cover. Finally, check the distributor rotor; it should be pointing towards the number one cylinder's terminal on the distributor cap, confirming the engine is at TDC for that cylinder.