Well first off, do you have the "5.4L" which is a
V-8, or the "6.8L" which is a
V-10?
In any event, headers are an excellant idea, as is a GOOD chip. IMO, there is only one GOOD chip, and for that contact
www.fordchip.com. You WILL be impressed. These guys ACTUALLY know Ford EECs, they do things to the programming other chip makers don't even know is possible.