SWEET2KSTANG· mm's nitrous mod
the 5.4 heads have larger ports as well, takes some finessing to get a 4.6 intake on the 5.4 head. the 5.4 "R" intake is set up for the 5.4 as well, you would have to hack it up to narrow it for the 4.6 too. that is a high dollar and rare intake manifold to be chopping up as well. the 5.4 ports are too much for a normal 4.6, it takes a good amount of boost or high rpm's to utilize it on a 4.6. you would be better off to get you set up worked over or go with just a regular c-head swap.