You would have to have a cab for each head,or you could use a stereo cab with one head connected to each side.Basically the same as using two cabs.Without some time of signal splitter in front, if one head has two inputs in one channel like some Fenders you could connect the heads via the second input.Connect the guitar to input one and run a guitar cord from the second input in that head to the input of the second head.But each head must have its own cab,or half of a stereo cab as far as I can see.I have used a Peavy 4x10 stereo cab in just this way,but it seemed to be more trouble than it was worth,to me.