So I am going to relocate my fuse box from under the hood to the trunk with the battery. My only concern is by moving the fuse box that far back will I need a thicker gauge of wire then what is OEM for the fuse box. I am not an electrical engineer lol so I am not sure exactly what will happen appreciate all your help

 

I have no idea why you would want to move your fuse box...? You would have to lengthen each and every one of the wires going into your fuse box (there are alot)... moving the battery to the trunk does not require fuse box relocation. If I were doing it, i'd probably use 2 gauge going from the battery to a distribution block in the engine compartment, then 4 gauge to the fuse box, starter, and alternator.