All of SA63 and RA65 were IRS. T Series are in the SA and F Series in the RA.
I am looking for a T Series diff and housing and don't really care what ratio, if a diff from a manual great as long as the diff is sort of healthy and can get another 200,000kms out of it I'll be happy...
PS. The first diff went after 500,000+kms and the second diff only lasted a month