The thread about Weld wheels and NHRA rules brought up by Big Dave got me rethinking the installation of my wheels. I plan on doing weekends at the track so maybe some long ARP studs may be needed. Does anyone know the knurl size of the 4th generation front and rear hubs? I also went out and put my 16 x 8 DragLites on the car and they won't fit with the available tire sizes. So off to Craigs List with them.

1970's, and most later, drum brake GM usually use a 7/16-20 thread stud on 4-3/4 x 5 bolt pattern with a 0.486" knurled diameter. Earlier drum and most disc GM cars use a 0.580" knurled section. You can use a common 0.500" (1/2") drill to check you stud hole - if the drill doesn't go through the hole, then you probably need the smaller knurl - if it does, you probably need the larger. If using OE length or a little longer, visit your local NAPA store and get Dorman studs. Dorman does make a longer than OE length metric stud (not as strong in tensile strength as the ARP or Moroso).

I use Moroso #46190 0.685 (Chrysler) knurled section with 1/2-20x3” studs, which are stronger than the 7/16”-20 on a 5 x 5 bolt circle. I don’t recommend the 5 x 5 unless you are running a big B-body like me or just want access to the Pro selection of wheels and slicks.


Big Dave