Check voltage at the starter while someone's inside turnin' the key. Then check to see if there's full voltage at dizzy, etc.
Recently, with my hard starting problems on my '65, I checked the wiring going to starter and found the purple ignition wire kinked with a couple bare spots down by the "S" terminal. Repaired that then checked out the firewall plug connector where the ignition wire and temp. wire, etc. come out. That plug was fairly corroded. After cleaning the plug connector, repairing the ignition wire, installing 2 gauge battery cables, cleaning all connections and applying dielectric grease, my no starts are cured.
If that firewall plug connector still exists on yours, take a good look at it. I've a feeling I had decreased voltage because of that corrosion. I'd bet if I only cleaned that plug and done nothing else, it would've been good.
If you still can't figure it out, maybe it's just a fair weather truck and you should move to San Diego.
-David
