Need help w wiring this alternator

[JBLEEZE33]

I have a 2000 escalade 5.7 and im trying to put a high output alternator from a 2003 5.3.. it has a plug w 3 wires comin off it and the stock one in my truck has one brown wire.. id like to run both alts but if i have to then id like to splice the end for the high output alt on to my wiring harness to make it work like stock.. can anyone (sunlit comet) help my identify the right wires to splice.. thanks