Hmm, my experiance with LS1's is that they get ahead of me low down, then when i'm in lift they cant pull away any further, or when i'm in lift they can't pull past me. They must be slowing down man. That's all I can think of. Those LS1's are still dinosaur spec pushrod driven, but the torque they have up top is insane. Unless that is, I haven't driven my old mans car without a full tank on board yet...