Hello, new to this site I have a 2007 4x4 f150 with 5.4 3 valve motor that sucked a valve on number 4 needs new piston and head, cylinder is in good shape. I have a 2000 expedition as a donor but it is a 4.6 2 valve I'm wondering if I put 4.6 heads on the 5.4 will I need to flash the ecu to avoid codes being sent and would a Ford dealership be able to do it for me any help would be great

 

You can't put 4.6 2 valve heads on a 5.4 3 valve block.

 

The second part of your question would probably present a greater challenge than the part @glc answered.