What are the exact specs of the amp? Before you go using wutever guage cables u got, you have to calculate it accordingly. Because you say your amp's running at 1000w, i'd strongly reccommend you using a 2 guage. Better yet...just go buy a whole new amp kit. When looking at the kit, it'll label how many watts it's for. That way you don't have to worry about which amp fuse u have to use.