Get onto a member here called "we wreck 81837s only". I know he recently fitted one to his HK Brougham. He will know what brakes work.

I'm pretty sure that you could fit VB-VL Commodore rear drums if you liked. I'm just not sure on the offset of the axle flange to the diff housing ends. The housing ends are the same as HK, but from memory there is no way the HK-HG drum backing plate will work. You might find HQ-WB go close, and you can run HK-HG drums on those. The drum backing plates will work with the HK handbrake cables too. The two major issues are going to be the hub diameter on the axles and the PCD of the stud pattern.

My recommendation would be to sell the axles you have to someone who prizes VL stuff (which I never understood, but they are out there). And get new axles made to suit either of your HK backing plates and stud pattern OR HQ-WB backing plates with your HK drums (so still HK stud pattern). Just choose whichever gives you the closest flange to flange measurement to the original HK measurement. I think the HK-HG backing plates will need axles that stick further out from the housing than the HQ-WB backing plates. I'm pretty sure a VL rear housing is about 20mm narrower than a HK-HG? Have a read here, the info is not 100% correct though so check before committing, eg they list a HK with a different diff width which is incorrect:

https://www.whichcar.com...ff-conversions-tech-talk

You could also get the new axles made to HQ-WB stud pattern and then just use HQ-WB drums - they are still available new. And this would allow you to fit HQ-WB rotors and HQ calipers to your stub axles. Means fitting HQ-WB wheels but you'll have better brakes.