That's not the ground - that's the main power cable! Thus, the fusible link.
The fusible link may be replaced with a fuse - for your 1999, the alternator should be rated for 117A max output (111.15-128.7A actual max output, given the "95-110%" range usually used.)
A MEGA or ANL fuse is preferred, 10AWG fusible link wire can be found in bulk, but is difficult (and you usually get clobbered with minima.) Use a 125A or 150A fuse in either format, mount it on the fenderwell. The other lead from the fuse can be run to either the PDC input stud (as OEM) or to the battery positive post (electrically speaking, they're the same thing.)
Do not eliminate the fusible link without replacing it in some manner!
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