Normal boost cars are below 10:1 ratios. You can boost 10:1 if wanted but 8 pounds is about the most daily wise. The 2003-2003 Cobra was a 8.5:1 compression ratio from factory. The 2003-2004 Mach was 10.5:1 ratio from factory w/o charger.
PS: LS1s are good engines, too bad the mach's would tear'em up.