Not all drive tangs are lined up with the dist. rotor the same way
You need to be sure you are on "no 1 ready to fire" and not no6
There are only two ways to determine that
1--If the valve covers are off for other reasons, bring the timing marks up to TDC, and look at the no 1 and no 6 valves. One one cylinder, they will both be closed, on the other they will both be "about" equally open. Whichever is closed is the cylinder ready to fire
2--Pull the no1 plug, stick your finger in the hole, and bump the engine until you start to feel compression. You may have to go 'round a couple of times if you are not familiar. When you start to feel compression, look for the marks which should be "just coming up."
Don't set the marks on TDC, but rather where it is that you want initial timing, IE about 12 for a dead stock cam, or 15 or more for a little hotter cam.
Drop the dist in so the rotor points to the "generally" front (small block) and align the reluctor wheel tip with the center of the pickup coil. Whichever tower the rotor points to on the cap is no 1. Be sure, of course, that the vacuum advance has "swing" room.
Firing order same as GM, 1 8 4 3 6 5 7 2 clockwise around the cap.
There "is" a factory specified no1 plug wire, but if the drive gear (in the block) is not in right or if the dist. is "made different" then this won't be quite right.
