What a coincidence I also want to do this - have a 3.5L Mazda engine in a 1990 90 but nothing else was changed meaning I could pull down a house even in 5th gear, always move off in second as 1st is just not needed.
Was advised that a transfer box from a Disco 200 would be ideal for me?
Any advice welcome and keen to hear how other people get on!!

Cheers
James