The LS series and new LT series engines in our Corvettes are incredible on so many levels. If properly maintained, they will last many decades of spirited use. However, abuse is a different story. It doesn't take much talent to over rev a motor, miss a gear shift, or do some serious damage to any engine. Fortunately we have rev limiters built into the engine management system, but that will not prevent someone from breaking a piston ring that would or could cause excessive blow by. A cylinder leakdown test and a compression test may find the damaged cylinder. We have all witnessed irresponsible Corvette owners showing off when leaving a car show or some other Corvette gathering. They will wind up their motor until the rev limiter kicks in and attempt to powershift their cars. They literally have no idea what they are doing to their Corvettes and the worst part is, in many cases they don't care. We all know these type of guys and we have said to ourselves, "I would never buy that car" because we know how it has been abused. Unfortunately the selling dealer doesn't know what that particular Corvette has been through, and you are the unfortunate second owner. If not cracked or broken piston rings, then it could be bad valve guides. Insist on having your potential purchase looked over extensively by a independent tech that you know and trust before signing any agreements.