I have a 1967 xr7 , car was turning over in 1 second , slowly car was taking long to start , drove it to store and felt weak and stalled out. Tried to restart and battery was dead . Put in new battery and started right up for a day or two after taking it for another drive I had same issue . I replaced the alternator and charged battery started right up, again for a day or 2. Took car for another drive and had same issue again , long crank to start and car feels like it wants to stall , until it is on the road at speed. Does anyone have any idea what I could check. Volt regular , alternator cables ? Thanks in advance .