Re: 99 4.0 Vs. 2010 4.0
Apples to oranges......totally different engines....
One's an Overhead Valve and pushrod motor. The other is a SOHC motor....so there's a cam in each head instead of a central camshaft.
BUT...if you're asking '99 Explorer compared to 2010 Ranger, then yes, it's essencially the same exact engine. '01 is when Ford finally put the SOHC in the Ranger....but it's been in the Explorer since '97.
'01 XLT disguised as a '03 Fx4 Level II.