I haven’t done mine yet but I have the HD steel tail shaft version for my ‘47. I want to keep the stock pedals with the clutch shaft, so I have a ‘51 Merc bellhousing and I’m staying with a side shift (so the longer case won’t matter). I also have a med duty version (Mustang V8) and a T150 top going into my ‘41 with a SBC. That one I found an Offy adapter to the SBC bellhousing.
This project got put on the back burner for a while. Thanks @Nailhead Jason for the good info on this.