what size knarl end fits in the factory front rotors on a 79 malibu and what size goes in a 71 12 bolt with stock axles, i wanted to use 1/2" all the way around and i ordered some and the head on them is way to big, i may even use 7/16" ones at this point it doesnt matter, i just need to know what size ones most of yall have used and part numbers if u have some would be great