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These firing order diagrams show rotor rotation direction and give the location of the number one spark plug wire lug on the distributor cap. The location of your number one lug may, and in fact, most probably is, different from that shown. Your number one lug is which ever lug your rotor is pointing at when your engine is positioned so that the number one cylinder is at top dead center at the end of the compression stroke, not the exhaust stroke.

To identify the alignment of the timing marker and the "zero line" on the harmonic balancer which represents top dead center at the end of the compression stroke, just remember that it occurs just after the intake valve closes. Remove the valve cover so that you can see the valves for the number one cylinder. Identify the intake valve. It is aligned exactly under the runner of the intake manifold. The exhaust valve is exactly aligned with the exhaust port of the cylinder head. Take precautions so that the engine can not start accidentally as you rotate the engine (i.e., take out the spark plugs). Rotate the engine and watch the intake valve go down. Keep rotating the engine until you see the intake valve just begin to come back up. Stop, your close. Look down at the timing marker. Rotate the engine just enough more to bring the "zero line" on the balancer into alignment with the timing marker. Your engine is now at top dead center on (at the end of) the compression stroke.

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