360 start up problem

What kind of battery? My son's 71 valiant had problems starting when we first got it and we changed everything: Starter, relay, battery. Then with advice from FABO/Moparchat we then went to Sears and bought a DieHard gold and it fired right up. Just because a battery is new, doesn't mean it is good.

I tried a red top and yellow top. Both worked on other cars. It turned out to be a bad ground. Now im just dealing with a 6 year old carb.