Starter not engaging

There are "Chrysler" shims that move the entire starter back a hair.... might just do it for you.
I've never heard of "Chrysler shims" and no official procedure for doing so. They are supposed to bolt right up and go. In fact NO starter than I know of that bolts up in this manner uses shims that I'm aware of, only the ones that bolt up to the bottom of the block with vertical bolts like GM

Frankly, I've never understood why GM could not make blocks and starters that fit LOLOL