Not sure if this has anything to do with breaking starters, but I have always used the big armature starters in my 340's and never had an issue. 727's, 833's, headers and stock manifolds. With and without dust covers or shims. Never noticed, but possible the cones are reenforced.
Yeah, you didn't see problems like this with the stock large gear reduction starters Chrysler used. Like I said earlier, the only reason I'd go to a mini starter would be lack of space.