Is this an HEI ignition ? Sounds like it is. The heavy pink wire has power with key on, from what you said. With cap removed verify rotor spins when engine is cranked , have someone crank engine while you watch rotor and verify. Next verify that pink wire stays hot while cranking engine. If these check. Verify that rotor is not burned ,remove and look underneath for arcing or carbon tracking. If any of this is present replace cap and rotor. The only thing left is the magnetic pick up in base of distbutor, what happens here is the wires will break internally and not provide a signal to the ignition module.hope this helps I’ll be around for a while so I can help if none of this checks out