Gearset, which electronic ignition do you have?
I ask so we know what power you are looking for.
If it is HEI, then you need a fairly heavy (10 ga) lead that's switched, some people use a relay switched by the factory resistor wire (or did those have a ballast resistor? I forget).
If on the other hand it's an aftermarket unit (I'll pick on MSD just because) and you are only looking for a switch to turn it on that's another deal.
Best of luck to you regardless.