Anybody know where I can get some of those plastic fasteners used for the airbox on a 350? This is the lower tray of the Y shaped airbox where the filters sit. It's mounted with 4 hex screws along the front edge and then two of these plastic fasteners at the back corners. They look just like the ones used on interior trim pieces that always break off when you try to remove them. Thanks!

 

I think you are referring to "push rivets". If so, I've seen different sizes of those at Napa and in the "HELP" section of Advance Auto Parts and Autozone stores. If you have an old one go size it up with what they stock in the stores.

They sell them online too, but you'd need to know the hole size to get the correct ones. For example:

 

That's it. Thanks!