Yes I see that.
I also see that your F-plate is a universal large diameter size, so it can supposedly attach any convertor to an SBM, and therefore any mopar trans. It seems the only odd man out is the starter....And yours does not have the notch, like the ones in the images I included.
I can't say your issue is the starter, only that looks like it could be, and that is why I asked about the friends starter.
As to the wonky crack, that is in reference to the missing notch.
The old style factory starters did not have that support work in that location, but rather, had a large window there and IMO, your current F-plate would be happy to see that Chrysler starter.
Of course we all universally abhor that; slow-cranking,cumbersome,wants to fall on your face, hates headers, overweight, pig of an OEM starter....lol
In any case
Happy Hotrodding