To do this you will need a wire brush a multimeter and a fair amount of patience. 1st make sure your distributor is installed correctly leave the hold down snug but you will have to be able to turn it. next using your wire brush clean the dirt and rust from your harmonic balancer if you have one of the V8 rigs you will be lookin for the mark that reads v8 if u have a v6 u will be lookin for the mark that says v6 line the appropriate mark up with the 0 degree or the TDC mark on the timing chain cover just like when your setting your ignition timing. Step 2 find the wires coming from your distributor there will be 3 of them. now on the harness side of the plug locate the tan or brown wire. Now set your multimeter to a 20 amp read on the DC side and probe the brown or tan wire with the red lead on the multimeter and connect the black lead to the neg side of your battery. 3rd switch on your key but DO NOT crank the vehicle!!!!! with the meter hooked up watch the reading as u gently rotate the distributor back and forth you will see the reading change from 0.05 to 5.02. The goal here is to set it on the 5.02 side just before it goes back to 0.05. this is where u need the patience. this worked for me after a distributor swap now my 3.9 is purring like a kitten.
I can't get to the connector to hook up the multimeter. So I just static timed it. Line up the mark on the engine with the one on the pully, lined up the rotor with the mark on the distributor.
Truck used to run, now it won't start. So I got to looking and it looks like the wires are installed on the cap one spot off, then the previous "mechanic" rotated the distributor to line up the rotor with the proper wire.
No problemo, I'm looking at the cap and rotor and thinking it's a good time for a tune up, so I'll get it all back to correct and static time it for fuel timing. Lucky I have a KLR to make tool and part runs with--beats working on a hot engine.