Changing my diff from commodore to Hq stud pattern

[bettythefbwagon]

I bought a diff a while back that was labelled as a shortened 9 inch for a FB. It's got commodore stud pattern and brakes but I'd like to change that to HQ to match the front. I've got a set of 14 inch HQ steel rims that I'd like to use. What's the best way to make that happen? I'm in no rush as it's my first project and I want to do it right. I've read through the forum a bit and I know that some people run HQ rims on Commodore stud pattern as it's not far off, but I don't want to snap studs. Any info would be great. Cheers, Josh

[gpi]

take it to a diff shop

i only use preston automatics and differentials in campbellfield

get them to swap the brake junction over to the other side while theyre at it

[Harv]

From what I understand, they can be redrilled (offset) and oversized studs used. From memory, Mr Black has done this in the past.

Cheers,
Harv

[bettythefbwagon]

Legend, thanks fellas, I’ll look into that in the new year!

[Blacky]

Hi Josh,

I have redrilled a diff as Harv mentioned from Commode stud pattern to HQ style , its quite simple if you have the gear to do it. we offset drilled the stud holes on an indexing mill , they are only 65 thou out and Coventries sell oversize wheel studs that still have 7/16" thread but oversize splines so it JUST fits.