But looking back on what amp you are playing, I really dont see why you'd have hug dips in voltage. I have more power than that on a stock alt....and no issues.
Check to make sure your factory alt is working like it should, and you have good connections.
Exactly!! Check your connections and CLEAN YOUR MAF. There's a lot of guys on here that saw drops in voltage simply b/c their MAF wasn't clean and idle RPM was off.
When you check your connections, clean off terminals and also scrape some paint where the ground points are.
If you are still running a lower voltage after checking your connections, have your alternator tested.