When replacing the windshield frame to the body on MGBs, the holes have to be in almost perfect alignment to install the four bolts that hold it in place. This is difficult (especially when the dash is in place) since it has to be done by feel. This is made much easier by substituting the regular bolts with tapered bolts.

The holes need only be aligned enough to start the bolt, which will then pull the frame into alignment as it is tightened. Suitable bolts are General Motors #39986997 or #14011722. These are easily found in wrecking yards holding the hood hinges to the fender of may GM cars of the 1970s.