Convince me to put a TKX in my Dart
The 4-speed console just has a section cut out of the side so it clears the A-body 4 speed hump and shifter, using a 4 speed console plate with the auto console is no problem (same thing I did).
And the console itself is still pretty much centered, I think the factory measurements only offset it slightly. The rest of the large offset in the shifter opening in the 4 speed hump is taken care of the by the shift lever itself, an A-body 4 speed console shift handle has a large offset to bring the stick back to the middle.
With my T56 the shifter is dead center in the transmission tunnel, and other than moving the console back to deal with the shifter location being further back on the T56 I didn't have any issues with getting the shift handle to sit in the middle of the 4 speed top plate on the console. If anything my B-body pistol grip shift handle is still offset slightly to the driver side and it still clears ok. And I would have been time and effort ahead to start with just a plain automatic transmission tunnel. I had converted my car to an 833 and added the holes and 4 speed hump and I basically had to make it back into an automatic transmission hump and then modify from there when I did the T56 install.
There are a few pictures back a couple pages showing the shifter opening and handle and the console location on my Duster