Changing my diff from commodore to Hq stud pattern

Includes clutch, transmission, propeller shaft,
universal joints, differential and rear axle.

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bettythefbwagon
Posts: 2
Joined: Wed Dec 02, 2020 1:27 pm
State: VIC

Changing my diff from commodore to Hq stud pattern

Post by 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
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gpi
Posts: 1131
Joined: Mon Apr 26, 2010 2:08 pm
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Re: Changing my diff from commodore to Hq stud pattern

Post by 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
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Harv
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Location: Sydney, Australia

Re: Changing my diff from commodore to Hq stud pattern

Post by 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
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
bettythefbwagon
Posts: 2
Joined: Wed Dec 02, 2020 1:27 pm
State: VIC

Re: Changing my diff from commodore to Hq stud pattern

Post by bettythefbwagon »

Legend, thanks fellas, I’ll look into that in the new year!
Blacky
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Re: Changing my diff from commodore to Hq stud pattern

Post by 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.
When you're faced with an unpleasant task that you really don't want to do, sometimes you just have to dig deep down inside and somehow find the patience to wait for someone else to do it for you.


Foundation member #61 of FB/EK Holden club of W.A.
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