In the UK the change over from the 8 bolt front and 10 bolt rear to the 10 bolt front and 12 bolt rear was 87 I believe. If they are the same year as you say they should share the same diff carriers. The ratios may be different but probably will be the same if the bighorn is a diesel. But this can be a good thing, provided you swap the both diffs!

I have petrol 4.56 diffs in my 89 Mk1 (was a 4JB1) in place of the stock 4.44 diesel diffs, compensating for the larger boots.

(apologise if I am telling granny how to suck eggs with the ratios)

Last edited by Matski; 07/14/08 11:00 PM.
1989 3.1 Isuzu Bighorn Hybrid

2" Lift with longer shocks
31.10.50R15 Recip Trials
Full 2.5" free flow stainless system
Front mount intercooler
Pump tuned
4.56 Diffs