Funster_2011V6

Interesting. To beef up the 5w20 rated bottom end without a design change, I wonder? Or is the boss not the new 5.0 block? I thought it was.

http://www.bobistheoilguy.com/forums...39#Post2183739

Unleashedbeast

This is no different in my argument about the 5.4L in the GT500. There is NO reason for a 5W-50 lubricant. I have done the research, and the UOAs prove that a robust 10W-40 lubricant is far superior to the cheaper base stock 5W-50 grades. Motorcraft 5W-50 quickly shears to a heavy 30 grade/light 40 grade lubricant in only 2,000 miles. It's sad to say the least.

This is why I chose an oil that would remain a 40 grade throughout it's usable life, have higher amounts of ZDDP that is commonly found in API SM/SN formulations, thus providing much better protection with less wear than current 5W-50 formulations on the market.

Amsoil 10W-40

This is what I use in the Shelby, and she loves it!

Unleashedbeast

UPDATE: I just posted in the thread link you provided us Funster, as I know a LOT about 5W-50 lubricants, and of course....how much it sucks!