Is a 2003 F 150 5.4 engine interchangeable with a 2005?

The 2003 engine would have 2 valves per cylinder but the 2005 has 3 valves per cylinder. I would recommend going with a correct engine. Check out the crate engines that Ford sells.

Does anybody really know what their talking about or are you just guessing. I have had this 2005 in a so called certified ford mechanic repair shop and their no better than I am all they want to do is throw parts at it. That's called H.A.M. work down on the farm

I have the same question but can't get a straight answer

Did you ever figure it out?