well, if the states would start using metric, like everyone else, it would all be in cc's, and there wouldn't be any confusion. If you ever want to convert either way, just multiply or divide by 16.6 Works for big motors too. Ex: we all know a .15ci is also a 2.5cc, .15 x 16.6 = 2.49, or: a 454ci is a 7.5L : 454ci x 16.6 = 7536.4cc (then convert to liters) = 7.5L roughly. going the other way just divide. 5.7L is a 350, right? 5700cc / 16.6 = 343ci, then round for error, 'cos that 5.7L figure is rounded too, so it's probly like 5650cc, or 5.65L, or something like that.