It all depends on how the distributor was installed last. If it's been removed, it may no longer be "clocked" to factory specs. When in doubt, pull the rocker cover on the #1 side, then turn the engine by hand until you see one of the #1 valves open. Keep going until you have one of the valves opening and the other closing. At that point you are 360 degrees out of TDC. On the harmonic balancer, mark the point where they cross. If you still have timing indicator next to your harmonic balancer it should be pointing to the TDC line if the cam has been set up right. Once you get the engine to that point, turn the crankshaft all the way around once (360 degrees) by hand and now the rotor in your distributor should be pointing at #1.
# 1 on the distributor cap faces to the FRONT / CENTER
Distributor- 4-3-2-1- timing belt 34 12 (looking at distributor firing order)
Number 1 on the distributor cap is the top post closet to the firewall. Looking at the distributor cap it would be... top row 1-3 bottom 2-4
On the compression stroke, bring number one cylinder up to TDC (Top Dead Center). Drop in distributor so rotor lines up with number one on the cap. Fasten distributor hold down clamp so that it is snugbut you can still rotate the distributor. Start engine andwith the use of a timing light set the timing to whatever specs the engine calls for. Tighten distributor hold down clamp.
Standing in front of the vehicle with the hood open, looking at the distributor, number 1 on the distributor cap would be at the 6 O'Clock position.
Standing in front of the vehicle with the hood open, looking at the distributor, number 1 on the cap would be at the 7 o'clock position.
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.
Assuming this is a 4.3L engine, standing in front with the hood open, looking at the distributor, #1 would be at the 5:30 position.
looking from the front of the engine the firing sequence on the distributor is 2,1,3,4 i.e the right hand terminal on the distributor goes to number 2 plug second one goes to number one plug third to number 3 plug and fourth to number 4 plug
Looking from the balancer to the rear of the engine it is at the front of the dist on the right.
1,8,4,3,6,5,7,2 Number one on the distributor will looking at it straight down at the 5 o clock position.
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.