Definitive answer about starter
 

Not sure if I'm in the right area. I'm new to the forum.
I'd like to find out, on the starter for 5.3s and others. But there is options for external or internal bolts to hold the Armature together. And I guess it make a difference for my starter.
what is the reason for this difference?
I hate to say this but I work in Auto parts for last 17 year's and no one has been able to give me a definitive answer
Thanks
Channing