ive been looking at getting 3.9:1 diff gears put in to my bf xt falcon,

I was quoted 1600 to have it done and an extra grand to put a lsd in as well, not sure if ill get the lsd done or is it worth doing?

is there anyone on here owns a ba-bf n/a falcon with the 3.9:1 diff gears (4 speed auto transmission), what's it go like with the 4 speed box?

at 100ks my falcon sits on about 1700-1800 at the moment, so if it has the 3.9:1 I'm thinking it would be around 2200rpm at 100ks?

Any one???

I'd be stuffed if I'd pay that mate.

I've just put together a ute diff (M78).
Reco LSD - $375
3.89 gears - $150 second hand
Diff bearing kit - $150

Yes you'll be paying labour, having not done a sedan diff myself I have no clue how long it'd take. New parts will cost more obviously. Probably better to find whole cradle from 6 speed manual turbo/v8 model, M86 (Stronger) LSD with 3.73 gears. You'll need the driveshafts and not sure on tailshaft. Should be able to swap the pinion flange over anyway. Better diff than what you've got

cheers for the info mate,

I was talking to a bloke the other day about it and hes got a xr6 turbo 3.43 lsd diff and cradle he wants 500 for it.

is it hard to swap the whole cradle out ?? and would there be much of a difference in acceleration with the 3,43 diff ?

No idea how hard the cradle is, like I said I have a ute so it's piece of piss. I'd definitely be looking for more than 3.45, it won't be much of a difference in acceleration and not worth the effort. The 6 speed manual diff should be an lsd 3.73, a nice jump over what you have.