cc, or cubic centimeter, is a unit of volume in the metric system, the amount of space something occupies. lbs, or pounds is the unit of weight in the US. You can not express cc in lbs. If you name a substance, such as water, or lead, you can calculate the weight of 520 cc of that substance in grams, then convert it to lbs. Water weighs 1 gram per cc. You can take it from there.