2 1/4" with power steering. The tubes are all over the box, so I had to ding a couple tubes and slot the box to move it outboard a little. It is tight, tight, tight. Getting the right K member is key to whether it will all work or not. There is just no room for error.

On a Hemi Dart project I did a few years ago, I moved the passenger side top shock mount outboard along with the fender well. That allowed me to move the engine to the passenger side some and gained head/valve cover clearance, too. You might consider that on your project. If I had to do it over again, I would have done that on my Cuda. That little extra room is well worth the work. And if done right, very few people would ever even notice.