I have a 76 FJ40 and am wondering what I would have to do to use the older birfields (68-75) as trail spares. Will they go right in as a replacement birf? Or will this not work. Also will the older front axle shafts work as replacements, would I have to swap the older shafts and birfs in together to make it work. thanks. On another note what would one have to do to make minitruck birfs fit, just a little grinding?