Tunnel question

Okay, I've been reading everything here I can find, but the Noob has a question. I have a 71 dart, was a column shift auto car. Nothing is in it right now and I was pondering selling the 727 and doing a 4sp.

Here is the question- Folks keep talking about needing a different trans tunnel. Why??? I have some ideas, but would love to get the straight stuff.
Author: admin