If you have electronic, you will have a box mounted on the fender with wires going from it to the dist.

Plug gaps are just like tires, they are a compromise between performance and plug life, just like tires are a compromise between traction(being softer) versus tread life(harder rubber).

The wider gap will raise the voltage available at the plug, producing a larger spark. But this means the ignition system has to be in top shape, and the plugs can't wear much or the gap will get too big and it will miss-fire. Too small a gap, and your spark will be small, but the plugs and the rest of the ignition will have a long easy life, even though your engine will not perform as well. So the gap is a compromise between the life of the plug and the performance of the engine. The electronic ignition has more oomph behind it, so it can stand a little bit wider gap than the old points style ignition.