A999 as a street/strip trans.

So a quick outer inspection shows a VSS instead of speedo drive, but when removed it is driven by a gear so I think that is a direct swap.
The HD extension housing has many ribs on it that may interfere with my early A trans tunnel.
And as it is much newer ('93) and for a truck, it has no tab for the floor shift shaft lower support bushing.
So, has anyone else made a different mount for the lower bushing?
And are all A904/A998/A999 tailhousings interchangable?View attachment 1715416949
You can swap another 904 tail shaft on it. I run the ribbed style you have with a cable shift in my 67.