Forgot to say the spring can be replaced with OUT pulling the head if you can find a true mechanic not a part changing technician as they won’t to be called now days
Before you do anything pull the valve cover out and check valve springs The 5.4’s are famous for the valve springs braking and yes it will cause no compression
You do know the crossmember and drive shaft won’t work the 2004r is longer also the 2004r is junk if it is stock it has a plastic center support that strips out transmission rebuilder for 40years