VZ Diff Replacements

[ThunderVZ0410]

I currently have a 3.08:1 ratio diff in my VZ ute and was planning on changing to a higher ratio diff, Is it as simple as just replacing the diff centre or will I have to change more things aswell?
and what ratio would be a good recommendation for acceleration gains without taking a massive hit in economy
Thanks

 

[Surfwagon]

If you a lot of highway the 3.46 might be best but if most of your miles are around town go for 3.73 for more fun.
Both can be found 2nd hand and the whole diff centre just bolts in.
"Warning" there are 2 different size doughnut flanges on the diff end.
All LS2 and VZ 6.0L run the larger flange, not sure about VZ V6's, difference in size shown in pic.
The 3.73 is only found in earlier VT2-VY2 HSV manuals.

 

[ThunderVZ0410]

Would a diff specialist be able to sort out the flanges for me or is that something I would need to arrange?

 

[_R_J_K_]

Best buying a complete diff with the gears you want already in it. If you swap out the gears you'll need to take it to somebody to get the backlash set properly.

The flange is something you should be able to swap yourself, use search as I'm pretty certain it's been mentioned a fair bit.

 

[Deuce]

You could give the center swap a shot yourself if you wanted:
https://forums.justcommodores.com.au/threads/vp-vz-how-put-together-irs-diff-diy-style-how-identify-lsd.217078

 

[figjam]

or will I have to change more things as well ?

Speedo recalibration .