I'm pretty sure it is electrical, and the fact that it started after you replaced the pickup kinda reinforces that. Can you tdc compression stroke #1 and see if you can get your timing as close as possible, once at tdc put a dot on the side of the distributor with a marker under #1 on the cap. Pull the cap and turn the dist. so that the rotor is just slightly before #1. The dizzy isn't 180 out is it?
