Yea thanks guys. I'm not worried about an original diff ratio I'm just after info/suggestions of the suitability of a 2.78 and other ratios with my other drive line components.
Maybe the 3.08 or 3.55 will be an option.

Do you suggest I go original axle and housing (without the eye hole thingo's) or go HZ type?

I can't wait to get a regular job back in Adelaide and drop this FiFo work, not much has been done on the car at all because I have been too busy with work. :(