You can find out in the repair manual for you vehicle.
#1 will be the first hole past the cap's mounting screw on the left side of the distributor, going clockwise.
it is bolted to the distributor just under the distributor cap.
Check the module under the distributor cap.
Standing in front looking at the distributor cap, number one would be at the 5 O'Clock position, from there clockwise it goes, 1, 6, 5, 4, 3, 2.
Get a shop manual. There is no distributor. These have coil packs.
18436572
On the 4.3L V6 the distributor is located in the back of the engine, in the middle. Just follow the spark plug wires and they will lead you to it.
1995 and earlier, standing in front with the hood open, looking at the distributor, number 1 would be at the 5:30 location. Clockwise from there would be 1, 6, 5, 4, 3, 2.
Standing in front looking at the distributor cap, number one would be at the 5 O'Clock position, from there clockwise it goes, 1, 6, 5, 4, 3, 2.
5-3-0-6-7-2
Standing in front with the hood open, looking at the distributor, #1 is at the 6 O'clock position, from there clockwise it is 1, 6, 5, 4, 3, 2.
It is right behind the Throttle body and just to the right of the distributor. The wire that is in the center of the distributor cap hooks to the ignition coil.