90-93 fuse box cover

The fuse box bolts to a rectangular metal frame that in turn bolts to the metal supports for the dash. It is just pulled down to check the fuses and then pushed back up under the dash. The black plastic fuse cover just snaps over the fuse box to kind of hide it. I doubt that you have the rectangular frame.

When I put my 90 dash in my 87, I didn't like the "tacked on" look of the 90-93 fuse boxes, so I just cut out a hole in my dash and mounted the fuse box in the dash behind the knee panel under the steering wheel. I don't have the metal brace that is usually behind the knee pad, so it worked out for me.

http://statefilingsoftware.com/pictures/fusebox1.jpg
http://statefilingsoftware.com/pictures/fusebox3.jpg