Alright, I took some quick measurements of the varying widths of a stock frame
This, on top of the fact that the frame varies in height from about 4" to 6.5," makes it difficult to get accurate measurements when you are putting something on that didn't originally go on an '84 BII.
My plan is to make the frame 1 width throughout (probably 33" or 34"). This will give about 4-5" of extra width for the motor to sit in. More room to work, and more room for stuff like headers. It will also move the coil mounts outward to better match up with the coil mounts on the FW axle.
Mounting a steering box outside this rail will also lead to a longer drag link and track bar.
My rough sketch of the new frame is shown below:
I have not ruled out the possibility of using C-channel instead of "boxed"

This, on top of the fact that the frame varies in height from about 4" to 6.5," makes it difficult to get accurate measurements when you are putting something on that didn't originally go on an '84 BII.
My plan is to make the frame 1 width throughout (probably 33" or 34"). This will give about 4-5" of extra width for the motor to sit in. More room to work, and more room for stuff like headers. It will also move the coil mounts outward to better match up with the coil mounts on the FW axle.
Mounting a steering box outside this rail will also lead to a longer drag link and track bar.
My rough sketch of the new frame is shown below:

I have not ruled out the possibility of using C-channel instead of "boxed"