HK to WB are the same basic stubs. Not sure about HD-HR. I have the specs for them all at home, if someone else doesn’t reply I’ll look it up.

See attached. These are CRS drawings and originally appeared in Australian Street Rodding in September 2005. I tried to attach the original article but .pdf do not attach. You can see Torana are 9.5deg KPI and HR-WB are 7.5deg. That is causing your alignment issues. You can see that the HK-WB stubs will lower a HD-HR by about 0.6", and will decrease your track by about 6mm.

If you run front discs you'll have to run 14" wheels regardless of whether you run HK-HG brakes or HQ-WB. However if you intend running front drums, your 13" wheels may fit over the drums, you'd have to try. If you intend running HD-HR front discs not sure if HD-HR calipers will bolt into the right spot on HK-WB stubs either, the discs will fit but you'd have to compare to check out the caliper fitment.