:SNSign: I have a 2001 F150 supercrew with a SOHC 5.4 backed by a 4R100 tranny. the truck is stock minus a k&n intake kit, true duals (cats work, no mufflers) and a diablo programer. I'm planning on putting a 2001 navigator DOHC 5.4 engine in it. from what I understand most everything bolts right up ( blocks are the same,) the DOHC heads should drop right in but the timing chain cover, intake manifold, exhaust manifold will not work from a SOHC engine. Belt drive systems on a SOHC engine ( A/C compresser, alternator, power steering pump. I'm not sure if they are the same for the DOHC, from what I've seen they "might" not a 100% on this. There is another possibilty so correct me if I'm wrong. A 4.6 SOHC or DOHC will fit on a 5.4 block as long as you use the 5.4 intake manifold. if so then I can expand my search to get DOHC heads on my truck. Can anyone shine some light on this?