Changing diff to commy

[HK1837]

There are mobs converting Borg Warner centres to fit HQ-WB Salisbury housings as well. I reckon this is a better idea as you get to keep old reliable rear drums and it all looks original.

[commodorenut]

There are mobs converting Borg Warner centres to fit HQ-WB Salisbury housings as well.

Diff Technics in Kogorah NSW are one of the mobs who do this. http://www.difftechnics.com.au/
You retain your original housing, tailshaft, brakes etc - all they do is update the centre to the LSD 4-pinion BW78 unit (aka M78).

The advantage is they use the stronger 4-pinion centre, which is the same diff that went all the way to VT1, so it had up to 220kw (in HSV 5.7L form) pushing through it comfortably enough to maintain a factory warranty period. I have a number of mates with early commodores who have had their old salisbury 5L diffs converted this way, and they're all happy.

Do u think the tailshaft would line up or would it be offset..

Early Commodore salisburys do have an offset pinion & the 2 axles are the same length as each other.
But these are the same centres that are available in HQ-WB, so theres no point even looking at them.

Later (VL onwards, and some '85 VK) Commodore Borg-Warner diffs, which are worth looking at, run 2 different length axles so the pinion ends up dead centre.

The Commodore borg-warners run a flat drive flange on the front, and require the matching yoke to be fitted to the end of your tailshaft (so the shaft will need shortening). If you do the internals conversion that Diff Technics offer, nothing externally needs to change, so your tailshaft remains the same.