Starter problem. 3 brand new starters later

I have a 1988 Ford Ranger

I have replaced the starter a few times, there is a new flywheel on the truck. Within days the starter engages really rough (metal on metal).

Sometimes the starter drive just clicks in and out. I've heard about shimming but whereabouts on the starter do I shim or is there another problem?

I've also been told to drill the holes out in the starter casing allowing me to rotate the starter either clockwise or counterclockwise. Any ideas?

I wouldn't drill holes in the casing. If you have any warranty that will probably void it, and it shouldn't be necessary anyway.

You can pick up some shims at a local parts store. You place the shim between the starter body and the engine block to move the starter further out. Good luck.