yup. you can do the big 3 upgrade on a stock alternator. How much difference that'll really make, depends on several factors. The typical reason for doing a big 3 upgrade, in my view, is to support more current flow with a higher output alternator, ideally.
lol ya but i still cant find the positive post on the alternator and no im not car stupid i do know alot about cars this one just has me asking for help.
In some cars, the main power and ground feeds are in the harness plug, and not a separate line. Look for a wire that's at least an 8AWG to 10AWG line in the harness that plugs into the alternator.
I did the big 3 in my buick with all 1/0 and stock alt/batt. Im running a 3000 watt system with minimal light dimming unless i really crank it hard. its definitely the cheapest and easiest way to squeeze a little more power out of your stock electrical. if thats not enough maybe try an overdrive pulley on your alt.