Wheel stud knurle?

[70net440]

Putting longer studs on my '74 Dart bracket car. I have Mr. Gasket part #4311 which have an advertised knurle of .620" I measured them and got about .615" The old studs measure about .045" smaller. I believe these are the original front disc brakes for the car, they are LBP. The instructions say for a Ford you need to drill the holes out to 21/32. Should I drill out my rotors or is there a different stud that is the correct knurle?

 

[70net440]

Forgot to mention the studs are 1/2" x20.

 

[bOb shingler]

if you have a dial caliper measure the knurled portion at the smallest diameter, between the points. go to your drill box and use a drill bit that's close but only on the smaller side. if i recall when i did mine it was a letter drill size. use a hydraulic press to finish the job.

 

[70net440]

21/32 bit did the trick,but one of the studs wiggles a little after being pressed in. Thinking about putting a small tack weld on the backside of the stud just to make sure it doesn't spin when I tourque down the lug nuts. Also just realized I misspelled knurl. Doh!