Need Help Re: Fuse Box
 

I have a 1992 4-Runner SR5 V6.

I'm planning to install a 160A HO alternator soom. There is a fuse in the fuse box under the hood that is labeled "Alt 80A". What exactly is this fuse for? Is it for the alternator? The stereo guys I've asked said it is not and that there should not be a fuse inline between the battery and the alternator.

What is this fuse? Does it have anything to do with the alternator? My manual says it's for the starting system and other things. Is it just an "alternate" fuse? Any help would be greatly appreciated.