Fine Tuning a 360 Magnum with a Brawler "Double Pumper"

Yeah my voltage gauge drops when my blinkers are on lol so I’m sure part of it is a bad ground, but doesn’t hurt to check. I think I’ll be getting a new alternator anyway because I want to run dual batteries with a beefy inverter (it’s a work truck but not slow is the goal here).
Find an alternator that's rated around 100A to 120A