Hello everyone I've been reading posts on this site for a couple of weeks now & you guys seem to really know your stuff so, I wanted to ask your opinions. I have a 2003 F-150 with a 5.4 engine. I'm running Ford 5w-20 till I get around 10000 miles on the truck. Right now I've narrowed my choices down to Amsoil 5w-30 ASL, 0W-30 S2000, or Shaffers 5w-30. I want to be able to run 8000 miles between changes. I know Ford recomends 5w-20 but I live in the south & also do a fair amount of towing. What oil do you recommend & when do you think I can start to extend the drain interval.