hey guys... thanks for tryin to help....first thing, where in the summit catalog is there headers for 98 5.0 X....second thing the hp is curtesy of alot of $$$$. ill give u the parts i used 1 by 1 when i make a list and find the receipts.... its not hard to pull ALOT of power from these motors....but it is hard to pull the motors from the truck(what ws for thinking, theres no room for this motor in this truck) but anyways the most power comes from whats in the engine not around it (intakes chips ect) although they do work together to biuld the power....but anyways ill get ya a list of what i did to make the power, the one thing i cant find is these darn headers.....btw, this site is great and u guys are all great help.......ttyl