Answers about my 17 mpg in my Burb.

[Baradium]

Originally posted by 68 Suburban
Since the owners manual was written 35 years ago before the advancement and research that goes into todays motor oil was known, I think I will trust what I have research about todays motor oil.

Show me one car or truck today that calls for 20w50, or even 10w40 for that matter?

You seem to be a big believer in amsoil, why not read about their 0w30?

http://www.amsoil.com/products/tso.html

Don't know about amsoil, I just want to try it. I've heard a lot of good things though.

The call for the lower weight oil to get higher fuel economy numbers, that is all. Show me one car or truck today that will last for as long as our trucks will. IIRC my dad's 91 Z71 w/ 350 still calls for 10W-40 in higher temps.