340 w/ 727 auto won't turnover

I know you said checked Battery, but those are tell tale signs of weak battery. With headlights on check battery voltage to see if you still have at least 12 volts. How old is battery? put a charger on it. Car sat for a week maybe something left on? I changed a starter in 1970 only to find out it was battery. So now I always go to batt. first, and its so much more accessible.