Shortie TH-350

Hi all, I'm swapping out the TH-400 in my rear engine dragster for a TH-350. I need to shorten the tranny about 2 inches, (I had to move the drivetrain forward when I put in the TH-400/500cuin. Caddy setup)
The 350 has the 6 in tailshaft housing and output shaft, can I swap in a 4 X 4 shaft and adapter/housing? What about the output shaft/coupler seal ? What parts am I looking for? stock, aftermarket ? Thanks for the help, Paul

Here's some pics of what I/m tryin'to work with...

This is the solution to my "shortie TH-350" post. New length is 26 inches OAL, real close to a 'glide. Paul