I was wondering if you found a solution to your (my) problem? My 68 does the same thing, starts all the time cold, but a few times won't after I have been out a while. It only happens only once or twice a summer. I just took her for a long ride, let it sit for an hour, and went out to go home. Tried to start her, and it makes no noise, no buzz no click....nothing. I just kept turning the key, and she finally started. When it happened the first time, I thought it was the ign switch, and I ordered a new one. Put in the new switch and it didn't work, so I put the old one back in and has been fine for about a year. My car is an auto, so I do have a neutral switch in the picture. I know the battery is good. Any info would be appreciated.