340 Starting issue
If you want help you are going to have to answer questions and be responsive. This is a two way street. NOBODY is paying any of us for our time here. I'm 74, so my time is more valuable now than ever.
1...Do you have a multimeter, some alligator clip jumper leads, a 12V test lamp and the factory shop manual? You can download that free, from MyMopar. That one and several others got there because of the guys right here
2...DO YOU have spark and how EXACTLY did you check that? This is IMPORTANT because of the way the Mopar key switch operates.
3...You say you have 'power' but we don' know how or under what conditions you checked power
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FUEL Do you have an understanding of how to tell if it is starving or flooding? Are you getting anything out of the accelerator pump? have you checked the plugs to see if they are wet/ other?
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COMPRESSION What shape is the engine in? Have you checked compression? Any recent changes, like a came change, etc?