Well, I thought with the front mount battery box I would be able to use the kit provided #4 battery cable. But now that it is pretty much done and doing some minor drive time, I have found that restarts when hot are sometimes difficult. Looks like I will go ahead and upgrade to a #2 wire. This is with a BPE 427 and cut off switch at the front bulkhead.

Looks like Battery Cables USA is pretty cost effective and when I pull the 2 cables (battery-to-Cuttoff) and (cuttoff -to-starter) and measure length I can get all the ends pre-installed.