I'm the guy that has droped a valve in 4 cases on a 350 chevy in a 1 ton.In all previous 3, valve seat gave up. Haven't torn present engine down yet. In one case a lobe on cam completley round and the lifter dished. This is an engine every 16 to 18 months. I do work my truck as with all my tools. I've always used Penzoil 30. Any body think I'm working the engine to hard and should I change to Rotella and or gas addative?
