Which ring n pinion install kit? 3.00" or 3.125" h

[AussieMonza]

Upgrading to 28 spline diff centre but not sure if I need to use the small head bearing or go to the 28 spline style?

Putting regular GM 3.73:1 gears in so am going to be modifying something or using the adaptor bearings.

Jegs list 2 different install kits
7.5'' 10-Bolt 77-81 GM Car & Mini Truck w/3.000'' Head Bearing &
7.5'' 10-Bolt 82-98 GM Car & Mini Truck w/3.125'' Head Bearing