1974 Hiace Diff Swap

[desh]

I read in an earlier article that the available gearing for the rear axle was 3.7, 4.11 and 4.56. I'm assuming mine is 3.7 (but would like to know how I find out) my plate says the diff is a G162?

My bus is very low geared, I assume for weight pulling as it's a minibus (converted to a camper) and it's quite a slow job getting any distance. I'd like to replace the diff with a higher gearing.

Any ideas where I can get one ?

thanks

desh