The adapter has a provision for a transmission mount.
Advance Adapters GM 4L80E Transmission to Dana 300 21 Spline Transfer case Adapter - 50-0432 Transmission: GM 4L60E Late Model (1997-2007). The adapter kit includes an adapter housing, adapter ring, new Dana 300 input shaft with 27 splines, GM VSS sensor, reluctor ring, O-ring, gasket, fastening hardware, and adapter instructions. This adapter assembly includes a new Dana 300 input shaft with 27 spline and replaces the existing stock Dana 300 input shaft.875 inch.