time to break out a multimeter:
check for 6V along the entire electrical path from the battery to the points to figure out WHERE the problem is:
assuming your car is wired up in the standard way:
with ignition switch OFF, check for 6V here:
- starter
- terminal box (on the side that is wired to the starter)
- terminal box (the other side - should have a black wire going to the coil)
- coil (side with the black wire)
- coil (side with red wire)
place a piece of paper between the point to make sure they stay open, then turn the key on and check for 6V at the points arm
if you have 6V at all those places, you should have spark (assuming the coil is good)
you can check for that by manually opening the points arm with the coil wire near a head bolt.
some common places where problems can occur (at least from my experience):
- armored cable NOT screwed in far enough to make contact
- armored cable screwed in too far & shorting out
- tab on lower plate shorting out against the distributor body
If you are going to be digging into the distributor, make careful note of the cam position (with a cam wrench fitted into the cam notch, note where one edge or the other of the wrench is relative to the distributor body - using a sharpie on the upperplate & distributor body helps) BEFORE you remove it, unless you want to have to set the timing afterwards.
You'll also have to remove the condenser before the lower plate can be removed - when doing that, it might be a good idea to superglue the insulating washer to the lower plate that the screw holding the condenser passes through.
If you DO end up having a short somewhere in the distributor, switch the multimeter over to ohmmeter mode to track it down - you pretty much want to have continuity along the electrical path from where the ignition cable plunger hits (the tab on the lower plate) all the way up to the points arm, but NO continuity between that path and ground.
