3 wire 10si alternator conversion

[TALLone71]

hello everyone,im upgrading from the external regulated alternator, to a 10si internal regulated 63 amp alternator. I have done a search on the forum, and see that the conversion is pretty easy and strait forward to do. my original wiring harness is from a 69 c10, and is in excellent condition, never been cut or altered, except for the fusible link at the battery, which I will be replacing with a new one.The only add on to the truck is a HEI distributor in place of the stock points distributor, and I am going to eliminate the stock resistor wire, and run a new wire for that. with that being the only modification to the system, has anyone ever had a problem using the original 12 gauge wiring and charge circuit. I had thought about upgrading the charge circuit to 10 gauge, but hate to cut into a perfect original harness, if not needed. I already have the plug and play conversion adaptor kit for the harness connections at the regulator and alternator. thanks!