Spend a few dollars on one of those diagnostic testers at Harbor Freight. Test the resistance of the plug wires. An old timer told me this trick. I have found even NEW wires to have too high resistance to fire properly! Aim for no more than 1.5 ohms of resistance.
I have also heard of guys waiting until dark to check things. Have a buddy open the hood and watch the engine as you are inside doing a light power brake....not enough to spin the tires, just load the converter a little. If there is ANY sign of light coming from any part of the wires, you have found a problem.
I had an off idle miss in my Frankenduster awhile back. The coil was bad in my case, but it also had a vacuum leak. I had changed the secondary spring months before and didnt tighten the screws to the pod quite enough.