This car should work out fine with 1 battery. Total amp draw with everything is about 80 amps. this is Full Tilt Boogie with everything on at once. I will most likely never run the car like that though. The Tuff Stuff Alternator does not have an Idle Rating for some odd reason. I have looked everywhere and can not find it. It has already been ordered but I think I will call Summit today and see if they have the specifications.
My 67 is set up with 2 battery's. Both battery's charge when the car is running but I have a switch by the shut off that will toggle between them. Just like a boat. The Megasquirt ECU has the capability to monitor Voltage so I could wire in a relay that would trigger a solenoid and bring the second battery into the equation automatically if it drops below a certain set parameter pretty simple.The 67 has more stuff going on. 3 fuel pumps that draw 20 amps each and a host of other things. If I recall correctly the amp draw on that one is in the 160 Amp + range at full tilt boogie.