[Old Henry]

Pull only one plug wire out of the cap. Start with #3. Then insert a short piece of known good plug wire into the cap that can reach a ground to make a spark. Start the car with 7 cylinders connected to the distributor. Does the spark from the short wire to ground seem steady or not? Use a timing light if you can't tell how steady it is. Do the same with 6, 7 & 8 one at a time.


This should rule out or rule in the plug wires. It should also tell you if the problem is further upstream particularly the cap & rotor.You've already tested that the coil output seems steady. So it's gotta be in the spark distribution system rather than spark creation system.[/QUOTE]

As I said in 3 posts ago (#70), I don't have a crab cap so can't swap wires around or pull one wire at a time from the cap to test it as would make sense. I will have to dismantle the entire wire loom to do anything like that. I may yet spring another $100 for another set of new wires like I just bought but wish there was a better way.