i know this is a newbie question but i couldnt find anything on the search part. What size piping would a 1998 have from factory. Mine has got the 4.6. I am asking because i have a set up with 3" pipe now and i want to go back down to stock piping diameter. Truck had aftermarket exhaust on it when i bought and i was just wondering the stock size. Thanks in advance for any help.

 

Someone told me earlier that 2.5 is the stock size on my 03, so i would assume its the same for your 98 but i may be wrong.

 

2.5" is stock for all '97 - '08 F150 trucks.

 

thank you very much it will help me drastically.