[DetroitDan]

I think you'd either have to take a measurement with some string, then look through a book or parts store computer for something thats real close, say an inch or so in either direction. Or just get a longer one, cut it and swage an end on it. I did see a part at Advance that looked like it had about 6-8 inch extension built in, if you have a cable a few inches too short.
I went through a pita trying to get one for my cclb, part they got me first was a foot too short, but it was measured and labeled right, near as I can tell the wrong part was in the right box. Did get the right one, but it's still not hooked up because I lost the little barrel clip that holds it to the brake cable from the wheel.

I wouldn't use a junkyard part on an emergency brake. Probably old and weathered and maybe weakened from past use. It's not just a parking brake, it's supposed to also be for emergencies. I stabbed the e-brake pedal once in an emergency when I lost my brakes, and the old crusty cable snapped when the full weight of the truck dragged against it. So then all I had was downshifting.