Wheel stud size??

Here's a repost from Tires and Wheels forum:

I'm ordering all the stuff for my front end rebuild. However, I don't know what the specs are for the wheel studs. I have Draglites, and need to install longer studs.

I know they are 1/2-20, and that I need 2.5 or 3" stud length, but what diameter does the knurl head need to be.....anybody????

It's a '75 Dart Sport, front disc brakes...