Copy/paste from another website -
The no1 cylinder must be on the compression stroke, and the no1 wire must go to wherever the rotor points. If the rotor is NOT pointing to the "by the book" no 1 cap tower, it will run fine, but if you want to do it correctly it simply is not that difficult and takes VERY little time
To time a SB Mopar:
1--- Determine that no1 is on the firing stroke and there are two ways to do that. If either valve cover is still off, look at either the no1 or no6 valves, with the timing marks on TDC. IF both no1 valves are closed, no1 is ready to fire (compression) and if no6 valves are both closed, then no6 is ready to fire. BE CAREFUL because the opposite two will be nearly equally open (used to be called "split overlap) and it can fool you
The alternate way to determine compression, is to remove no1 plug, stick you finger in the hole, and either bump it on the starter, or wrench it around until you BEGIN to feel compression. You may need to go around once to be sure. When you start to feel compression, pay attention to the timing mark, and slowly bring the engine up NOT to TDC but to where you want the timing, IE 10-12 with a bone stock cam, or 15-20 with a hot cam
2---If there is any reason to suspect the distributor gear is in wrong, or this is a new build, bring the marks to TDC, and check the position of the slot in the gear. IT should point to the far left (drivers side) front intake manifold bolt, which is a close as you'll get to "straight ahead." If it does NOT, as the poster above suggested, just take a big screwdriver and "walk" the gear up out of the helix, and correct it
3---(If you performed step 2, back the engine up with a wrench about 1/8 turn, and bring the marks back NOT to TDC, but where you want the timing.)
Next, with the rotor pointing towards the area of the "by the book" no1 hole, and the vacuum can "in the clear away from the firewall, drop the distributor in. By rotating the distributor body, you should reach a point where the vacuum can is clear of the coil and the firewall, and the rotor is pointing to the no1 cap tower
4---Now, if you have points ignition, use a test lamp or ohmeter, rotate the dist. RETARD (cw) and move it slowly ADVANCE (ccw) until the points just open
If you have breakerless set the dist. so that the reluctor tip is centered in the pickup coil.
5---Start the engine!!!! Notice that I did not say, "prepare for fire out of the carburetor," nor did I say "screw endlessly with the distributor for hours on end."
If you followed this correctly the engine should start!!! and run!!!!
6---Now take your timing light and adjust the timing as necessary.
