The fuel pump mounting studs are threaded into the head so they should come out fairly easily. If the studs aren't long enough to allow two nuts and you have a grinder, reduce the thickness of one or both nuts by a millimeter or so. If the gaskets on each side of the spacer aren't glued to the spacer, cut them out to get a little more stud length to work with. I suspect you have removed the valve cover, but if not, do so. Makes working from above much easier.