1981 Nissan Truck

If the motor is the NAPS Z22 motor like my 81 had, then the motor has 8 spark plugs. The distributor has I1 I2 I3 I4 and E1 E2 E3 and E4 on them. The I are igniton the E is exhaust. Put the corresponding wire to the right of what it says on the distributor. The motors cylinders are numbered 1234 from the front of the motor to the back. Exhaust is on the right when your looking at it. Intake on the left under intake manifold. Hope this helps.