Gears are not "tricky". Use the MHD method and they will be a lot easier to set up. All you need is a set of Ford gears(they come with the new pinion crush sleeve, pinion shims, and pinion nut), 2 quarts of gear oil, and a tube of RTV. I got my 4.10's (8.8) from www.stangstore.com fro $150 shipped. I spent a total of $170 on my gear swap. I then used a speedcal $90.96-98 auto can use a 21 tooth speedo gear for 3.73's, 4.10's need chip. Newer mustang autos also require chip.