More electrical problems.. :(

[71GeneralMotorsCorp]

hey guys, need some assistance. My truck has been down for quite a while, and I've been putting all new stuff in, and I'm down to the final stuff.. I've replaced the cap, rotor, ign control module, coil, main power wire from battery to starter, starter, power wire from starter to distributor. All grounds are clean, but my truck just cranks, with no fire. I get no power to the distributor, all I can think that is left is the battery, external voltage regulator ( the one that fits on the core support), or the ignition switch. Please help me figure this annoying problem out, I'd really appreciate it!