I bought my set from Inline Tube. They have an ebay store, search under 1970 Cuda Emergency Brake Cable. Tired to attach a link.

http://www.ebay.com/itm/70-71-E-body-Cuda-W-inner-E-Emergency-Parking-Brake-Cable-Set-Kit-OE-BSH7001-/200914282690?fits=Year%3A1970%7CModel%3ACuda&hash=item2ec76ca8c2:g:X-8AAOSwvgdW2ytK&vxp=mtr