Like everyone else I can't tell the dia. from the picture but I can see that the ruler shows that they are very close to 3" long.That is the same as the early non EGR valley tray bolts and much shorter than the stated length of the starter bolts @ 4 21/32s. I think that the later EGR motors do use two different length bolts for the valley tray.I know that GM has at least 3 lengths of starter bolts for different apps. and they are all knurled just above the threads,these don't appear to be knurled.