1974 duster 440 wont start HELP

I think the first thing I Would do is check all the grounds if you only have one ad two more at lest.. of all the years I have had mopars I have never had a pickup in the dist, go bad unless I was welding close to it with a bad ground hook up.I have had the control boxes go bad(orange box)but most of the time it was because of a ground..that's if your getting a weak spark..try to hot wire it that should tell you if its any of the things you have dun.and if you get in the dist,poking around make shour you have a brass feeler gage.most feeler gage sets have them in there..dont give up I'm shour it's something were over looking.hay maybe it's the ignition switch its self??