I would imagine that GM had a very specialized machine to do that very job,I have a new fan shroud that showed up in two peices and looking at my original it also has staples,I think what I'm going to do will be to straighten the staples on the original shroud and drill holes to match in the new shroud and carefully install and crimp them with whatever type of pliers work the best and would probably would do the same thing in your situation because I don't think you'll find a stapler that will do that job! Good Luck! KillerDave