A few interesting links containing shimming and relocating of oil pump. You will need to page through the threads from start to finish to get the full contents; sorry I can’t recommend any of these mods, as I haven’t done them myself. How did you get on with finding a crankshaft?
http://www.forum.mkiiisupra.net/showthread.php?t=13249&page=2&highlight=oil+pump
http://www.forum.mkiiisupra.net/showthread.php?t=14379&highlight=oil+pump