Lots of the SoCalXJ guys run Ford 5.0 injectors. Not for performance... only 'cause parts for the 5.0 are cheaper. They buy from here: http://www.fiveomotorsport.com/

IIRC, 19lb works for an unmodified 4.0 engine. There are a number of 19lb choices, however, and I don't remember the part number.