I was wondering if any of you knowledgeable gents know the final drive ratio of a 2litre box? Also is it possible and are parts available to change this ratio with the intent of giving lower engine revs at highway speeds? thanks...Rob

http://www.albinsgear.com.au/index.html 

This link may help:

http://www.aussiekombicampers.com/faq.shtml#kac_watkgr 

hth

4.57 is the diff ratio and the ones I have seen counted out at .89 4th gear ratio.
Albins has many ratios to do what you ask(around $400 last I got one) and I believe there are other 2lt 4th gear ratios but have not seen any myself.
1800 and 1600 boxes had .89 and .82 ratios but are not interchangeable with the 2lt.