OK so I have decided to go Synthetic 10W / 30 for the Blazer 350 V8. And I spent a lot of time watching Youtube on the series "Project Farm" and others, and no matter how you toss it Amsoli seems to come in lead. So if you go to Amazon, there in is the snag. When compared to the next highest raking oil "Pennsoil"10W/30. The situation is there is no way to get any feedback form anyone who's bought it in the past. That's because no one can buy Amsoil unless your in the club, despite the fact that Amesoil cost 3 time the best synthetic oil on the market. So all I'm going to get is A. the Amsoil local rep. and but the cost is the same 3 time as much as the second best Pennsoil 10W/30. Of course you can become a Amsoil special customer which costs $20.00. Personally I get a headache looking this whole thing so I bought a 5 GT jug of Pennsoil 10W/30. Crazy . . .