I did my big 3 a little different. but not much, I went from Alt-Bat, Bat-frame, Bat to firewall and used the factory braided ground to the block.
the black cable is going to the frame, the silver to the firewall, the blue to alt... the smaller guage wireing is for the MSD 6a. Soon the LS1 fans will also be hook up to that jungle of wires.
used a factory stud on the firewall that had a braided ground to the back of the engine block
since hooking the ground to frame it sounds as though the fuel pump pre-start purge has picked up in speed... always a good thing when the fuel pump can recieve more voltage.