It is called a test plug. You need a 2 inch one. I got it at Home Depo in the plumbing section. If you have a problem finding one let me know and I can ship one to you. The plug is like 3 bucks. You can also go a plumbing store and I am sure you can find it. Call PPE I am pretty sure the airbox mod will work on your truck. You can also do a search on this site and others and you will find the airbox mod. Look up Kennedydiesel and they also have an airbox mod. Hope this helps.