I personally hate rebuilt starters. Go to the boneyard and get one, clean up the flywheel with a dremel and rock on!
Don't understand your logic with this comment.I own a starter/alternator rebuild shop and have so for 22 years.you talk of buying used units.do you have any idea how much life is left in them????
Also a lot of the chain stores are getting their units from overseas or some cut rate re-builder who uses the cheapest quality parts to rebuild with.
For the OP,,your model truck uses a fender mount solenoid that makes the starter engage, try replacing this first.As for the flywheel ,,leave it alone.In my experience I have never seen a bad flywheel that prevented a started from disengaging,it is usually just the opposite they will not engage.Also something else you might want to consider.on ford truck the starter bolts to the bell housing ,not on the motor like a GM product.check and see if you bell housing has move a little.If it has you bendix clearance could be to tight preventing starter from disengaging.
Another thing I have noticed on several vehicles,,ford/gm/toyota//..the teeth on the ring gear is wore down this prevents a proper engagement of the bendix to the flywheel.if possible compare the length of you flywheel teeth to a new one.You may be surprised.
Also the only time a ford stater needs shimmed is if the thrust bearing is worn out in the engine allowing the crank to move front to back.generally the only engine with this problem was the 300 ci 6 cyl