The 468 is an aftermarket aluminum block motor. Totally unecessary and a big expense for a Gen III unless you're wanting to cut weight, factory blocks are more than adequate. Thiteks aren't cheap, but I'd venture to guess you could get the cfm needed from an Apache/Big Gas/HellCat head. The 468 I posted wasn't maxed out, it was still using a factory intake (ported) and 12:1, room for more compression and a better intake