I was always under the impression that the cases were pretty much interchangeable. The primary difference between the Hemi box and the standard 833 was the input shaft and gears inside the trans. The input shaft diameter and teeth count is the fastest, easiest, and probably the most reliable method of determining a Hemi box. If the input shaft is correct, everything inside the box pretty much has to match. Once you have seen a Hemi 11 spline input shaft, its pretty easy to identify the difference between it and a 23 spline input shaft.