Aftermarket Autometer 2494 Speedo. Or rebuild. Arrrgh!!

I am now considering an aftermarket mechanical speedo. Currently hovering around the Autometer 2494. Instructions sheets says cable requirements are 5/8 and 18. And cable needs to be a .104 square. Does anybody know what cable dimensions are for stock mopar cables? I am wondering if a stock 67 cuda screw on cable would work?
I am tempted to go GPS but I don't think that's my style
Neal