V6 vs V8

Today's V6's can create the HP, but they will never give you the TQ of a V8 and that's what gets you moving (at least without a power adder). Those new V6's also come backed with 6+ speed trannys so they can stay in the power band of the engine more often.

As for ford and the 5.0L, that's not a Windsor 5.0L with fancy heads on it. It's based off their 4.6L mod engines as tech857 mentioned.