On my 90 4.5 it was about the easiest domestic starter I ever changed. Just a hint, be sure to check the ground cable that mounts to the block and rear starter support for corrosion. (Don't ask how I know this!)
on my 1986 4.1 you need to remove the service plate under the car on the drivers side (3 x10 mm bolts). that will give you access to the starter and a/c compresssor. Not too difficult to replace and be sure to check the ground cable as well.