Brian,

Use a jumper wire directly to the coil from the battery; that way you know you've got voltage there regardless of anything else going on. Pull a plug and ground it so you can see the spark. What do you have now? If it is still weak, you can remove the jumper; the problem is not the supply to the coil -- turn your attention to the points and the secondary. If the spark was healthy, turn your attention to the feed circuit. Continuing as necessary, pull the coil wire and use a screw driver to cause the spark to jump to the block. That may be a bit vague; what you want is to see the spark from the distributor end of the coil wire as a helper (or you with a remote switch) turn the engine over. Careful, it can bite the SH** out of you. Got spark? That would verify the points are operational -- look to the distributor cap and wires. No spark; lift the condensor lead off the points. Does it spark now? No; your points or the wire is grounded or a low resistance to ground. Yes; the condensor is kaput.

Besides all that, do you have the correct coil? A low resistance (below 3 Ohms) primary will require a ballast resistor. If the coil primary reads 3-4 Ohms, no ballast is required. A coil that requires no ballast but has a ballast installed will produce weak spark.

I hope that helps some.

--
Mr. Shannon DeWolfe -- (I've taken to using Mr. because my name tends to mislead folks on the WWW. I am a 52 year old fat man ;-) -- KD5QBL