Hello, i have a 99 f-250 with the 5.4 v-8. I have recently Diablo Sport chipped, K&N filter charge and straiht piped it. The problem is after all of these modifications its still slow. It wont break loose on corners nor will it at a stand still. I understand that i purchased a truck i know that but when you see the same truck with the same engin kicking your butt with no mods theres somehting wrong. Im not the only one with this problem either. After tlaking to a few buddies i heard a rumore of mid year ford switching ou the plenum, located on the top of the engin, also has the fuel rail atatched to it. Does anybody know where i can get a performance rail? or anyhting i can do to the truck that i havent already. Im want to do things that will help me out possibly find a whole new engine without acually spending the few thousand for a supercharger. I 4x4 and i dotn think a SC is a good idea. Thanks for your time and i look foward to hearing back from you.
S

 

 

why is 4x4 and a supercharger a bad idea?

 

[updated:LAST EDITED ON 11-Aug-02 AT 11:22 PM (EST)]He's probably worried about the amount of heat a SC makes, it has been a problem when doing heavy offroading. However, today's technology should allow you to run a SC much cooler under any circumstance. There are many reliable intercoolers sold for a SC that would eliminate the tremendous heat and produce much more hp.
For the plenum, I think it is the heads that were changed after 99 on the 5.4. Ford calls it Performance Improved. Something about the way they were honed created that extra hp you're looking for. I don't think you can just switch heads, though. Maybe your best bet would be to have a shop hone your heads. Good luck.

Check this out.... https://www.ford-trucks.com/dcforum/DCForumID14/152.html