Severe engine miss at 3000RPM

[richd]

The same could be said for any two adjacent (in terms of firing order) cylinders, correct?

The firing order on an HO engine is 1 3 7 2 6 5 4 8, so 1 and 3 should never touch, 3 and 7 shouldn't, 7 and 2, etc. You mention 5 and 6 specifically because the cylinders are physically close making it more likely that those wires will touch.

If they do touch and voltage leaks across then you could get spark on the compression stroke of the trailing cylinder, prematurely burning some of the fuel or even causing detonation.

Is this correct? I'm just trying to make sure I understand.

Thanks,

Rich D.