In order to install the front and main boxes, the body must be lifted from the frame. We underestimated the amount that it needed to be lifted which dragged out the process some as we tried to fit these pieces several times...each time lifting the body just a little more. In the end, we determined it needs to lift about 2", primarily from the rear.
In addition to the body hold down bolts already removed (the two trunk bolts, the bolt under the steering column, the steering column from the dash, the seat belt anchors, and the bolts on the outriggers), you must also remove the bumper support brackets...all three supports per side.
With all body attachments removed, we used a porta-power at the roll bar bulkhead...
...then shimmed between the body and the frame so that we could remove the porta-power to install the main box.
The front portion of the main box goes in first. We had to lift slightly with a pry bar at the front body mount to slide it into place.
The main box goes in from the side, is slid forward to clear the rear spring mount, then back far enough to line up the front of the main box with the rear of the front box, then forward to fit the main box into the front box like it was before the temporary screws were removed holding these two pieces together, and into final position as a unit.
We found that we needed to trim about an inch off the vertical stiffener in the main box in order to be able to slide it forward enough to clear the rear spring mount.
We determined that the main box could either fit above the rocker rail bottom "C" section, or below it. We decided to fit it above it. This way, we could stitch weld the main box to the rocker rail. If it fit below the rocker rail bottom "C" section, we could only rivet or plug weld the main box to the rocker rail. Also, this way we didn't have to notch or cut holes in the bottom of the fiberglass rocker panel to accept the rivets.
With everything in position, Paul stitch welded the main box to the rocker rail and to the front box.