Ticking In Cylinder #8(1965 Mustang)

[beano.cok]

Recently I noticed a ticking noise when the car was idling. By disconnecting the spark plug wire from the distributor cap, one at a time, I was able to isolate the noise down to Cylinder 8. In an effort to troubleshoot, I first swapped the spark plugs wires(#7 and #8). I then swapped the spark plugs #7 and #8. After both of these steps, the problem remained in cylinder #8.

So my question is what could be causing this? I have read a number of different posts suggesting anything from the plug wire going to ground, to exhaust leaks, to very bad internal issues. Of the possibilities, which ones can I rule out since the noise disappears when I disconnect spark plug wire for cylinder 8.

Any ideas/suggestions would be greatly appreciated.

-thanks
Glenn

 

[horse sence]

Check it at night ,you may see sparks from the plug wires arching

 

[1995cobraR]

Is it a solid lifter cam or not?

Do not swap plug wires from #7 to #8. You'll screw up the timing. You may have a miss in #8. Pull the plug and see if it fires (place it close to the block). If not, try a new plug and a plug wire.