Just had my engine rebuilt, completely, everything except the block is brand new. The guy who rebuilt it has given me a 12k mile 12 month warranty with it, but insists i use Texaco oil 10w30. Any thoughts on this? I know 10w30 is listed as ok in the manual, I just dont know about the Texaco. I bet its better than Pennzoil!! lol In any case to avoid voiding the warranty I have no choice, but he didnt take to my suggesting the 5w30 Castrol GTX....