here īs a pic of the blockoff plate for the t-case
and here is a pic of the tailhosing block off plate.
you can see the difference in bolt pattern... I belive there is to kind of bases for the tvin shift.
I am planing to run the duals with the 350. I have a 23 spline input, a addapter plate from the 700auto .... I have a 4.7 23 spline for the second case, and a heat treated output shaft.... I hope that will hold up...