I have an au fairlane with auto 6 in it.

I'm picking up some 18's with fresh 235/245's off an AU V8 and I was wondering if it'd also be worth getting the LSD diff off it. It's only done 165-170000k'

What are the standard ratios on an I6 and v8? And what would the overall effect be of changing the diff? I've never played with diffs before so I'm a bit ignorant. LoL.

is the v8 a fairlane, ghia, xr8 or Fairmont /base model??

a lot of ghias/fairlanes don't always have lsd unless series3 or optioned due to traction control.
base model v8 or Fairmont run live live axle so those wont fit.

series 1 v8 ghia irs is 3.23 non lsd... series 2 onwards v8 irs are 3.45. and all xr8 are 3.45 lsd

the 6 cyl fairlane, ghia and xr are all 3.45.
the fairmonts are 3.23 and base models are 3.08

Both cars are fairlane ghias. Mine is a 99 and I'm quite sure the v8 is too

More than likely the v8 will be 3.23 non lsd.. I have a 99 v8 ghia that im wrecking and it has a 3.23 non lsd