Could someone help me with this?

I have redone the gas tank because it was horrible. I'm sorry I forgot to mention the car it's a 1973 dodge dart custom 225. I will check the battery cables I checked them almost six months ago when I changed the battery and the alternator. 67dart I'm gonna try that I believe I had a voltmeter here if not my father will have one I could use. The car ran fine for the past few months till just about a week ago and it's my daily driver. Thank you all for your responses.