Power and Ground

Hey guys, ive got a 1200W sony amp with the matching 12" 1300W peak sony sub, I have my power cable from the bat, to an 80A fuse and to the amp i beleive it is 4ga wire or maybe even 1ga its thick shit and not so much my problem, my ground cable is 1ga($100 battery cable i cut ends off of) but it will not fit nicely onto my amps ground connection(its about 1 cm wide with the screw that titghtens the wire against amp terminal. It took a while to trim the ground cable to fit around the screw and will barely tighten however if i make any sharp turns in my car the cable loosens and always flings off because it is soo fucking thick, if i were to trim more loose strands so it will fit nicely in the terminal am i gonna create any sort of draw from lack of connection, or is it gonna work just like normal. The only connectors that will fit into my amp are 8ga(alot smaller) so if i decide to use those connectors and trim alot of the ground cable to fit in and be soldered to the 8ga U-Connector is that gonna cause issues?
Thanks,
TheLonelyHalfCat:loser:

just get 2' of 8 Ga ground wire