So I spent a good 6 hours installing a new catless uppipe last weekend and making sure I didn't screw anything up...but alas...i failed It appears I forgot to tighted down the screw plug in the EGT bung and it came loose and fell out.

So does anyone know the correct size bolt i'll need to replace it so i won't have to make a trip to the hardware store while i'm in the middle of tearing everyhting off again? I want to be sure. I'd really appreciate the time saver.