1967 350. Powerglide. Stock.
Late last summer, the car started running like crap. Let it sit over the winter. Checked the spark plugs. Looked fine and that was about the exent of my engine diagnostic abilities. Checked the carb air/fuel mixtures and it didn't seem to do anything to improve or worsent the engine behavior. Hadn't driven it yet this year, other than to confirm how poorly it still ran. Can't even drive it, as it felt like only half the engine was running. Finally took it to the shop this week. They found bad spark plug wires that were causing 4 cylinders not to fire. These were original wires, so I guess they wear out after 40 years.
Waiting for a GM part to arrive from Denver, but in doing some more diagnostics, the mechanic found that even with good wires, a cylinder isn't firing. I don't know whether there is a spark at the "dead" cylinder. Part of the original diagnostics was to check the vacuum, so I'm assuming that that's not the culprit (assuming that vacuum could have an effect -- clearly, I'm not an engine guy).
Anyway, with this very incomplete diagnostic, any ideas on what I might expect as the reason why I have a dormant cylinder?