don't know if you fixed your problem, had this problem with mine. turned out to be the nut on the backside of the ignition switch was not tight, tightened it up and have not had a problem with it.

 

ha, thats funny i posted this same topic and didnt get hardly any good advisereplys. Well im having the same problembay68 and i replaced just about everything but the ignition. I am 99.9% posative its your ignition. Its very easy for people to guess at what it is but unless you encounter the problem you really dont know. Buy an original or a repro other than drake scott because theyre ignition repros are crap and will go out like that.

If its doing nothing, try the hot wire trick by connecting a screw driver to the two posts. if it trys to turn over then its your ignition. Try this. Put your key in the iginition and if it wont turn over with the screw driver trick then try it with the key out and if it turns over then, then you have eliminated it to your ignition because if the key is turned all the way on and no connection its not completing the circut and is broke.

I believe the ignitions are fairly affordable. But its better than replacing a new starter, solenoid, voltage box, ext.....
could also be a wiring problem if not the ignition.

hope this helps somewhat.
1970coupe