I'm working on my buddies 1997 GT with a 1998 Cobra swap. He just bought it the other day and only made it half way home before it died out and he had to tow it the rest of the way. When I started looking at it, the battery was completely dead so I suspected a bad alternator. Charged it up and when I try to start it, i just hear a big thunk and all the lights dim. I have tried charging the battery more, and putting a different battery on it. I also tried jumping the starter, when I do that, it clicks but not as fast as i think it should. When the thunk occurs, the crankshaft moves a few degrees and I can turn it with a wrench so the motor isn't seized up. I'm suspecting a bad ground or a bad starter but he's on a budget so I don't want to start throwing parts at this thing. Anybody have similar issues? I'm not familiar with fords at all.

 

try a voltage drop test on the starter, but you probably have a major loose electrical component somewhere