1978 c10 firewall bulkhead wiring questions

[cagodinez]

Back when I pulled the big block out of this truck I thought I would remember everything and figured the LS would be going in, in a couple months. Well here we are 2 years later and Im just barely doing the wiring on it, of course I didn't label anything. Can y'all help me out with this? Starting at the bottom of the bulkhead I have a tan and a dark blue wire, do I still need these for my 5.3 4L60E swap? Going up next I have a brown wire that use to go to the alternator, do I still need it? Directly to the left wire I have a heavier gauge red wire that use to go to the alternator. Next I have a purple wire, pretty sure that's going to go to the 5.3 starter. Directly to the right of that I have a light blue wire almost see through, not sure what that one is for? And the last one is a heavier gauge white wire, looks like it was feeding the distributor or coil, can I use this for 12 volts ignition source? Any help greatly appreciated.