rear disk brake cable

Finally put the 8 3/4" rear end in my 69, Big thanks to Dartman. Now, I need a longer rear disk brake cable then the one that came with the summit brake package. where do I find the long cable that will hook into the rear disk brakes? Also, I have a complete stock rear end, is it worth keeping? selling? and the fronts are big bolt disk brake, even though someone did the swap, I had all new painted parts that I changed, if someone needs a front big bolt setup for the fronts, everything but LCA.