That sucks, try loosing the bolts just a little and see if it works. Maybe gently tap on it when it's a little loose. Hopefully it'll free up.

The last couple starters I have bought were from the parts store for like a 90 dakota and I don't remember grinding on the starter. Got got rid of the big connector/90 degree thing on the electric connections. Otherwise they fit and have worked great for years now, one of them are at least 10 years old. Never got that kinda of service out of original starters, not me anyway.