Damn this is going to be much more of a pain than I thought it would be. I got the majority of the rust off using a center punch and scraping the rest with a razor. I kinda damaged the thread on the bolt by trying to turn it with a vise and my stud extractor, so the welded nut might be out of the question, I also dont want to risk welding the block surface since I have no experience welding anything. I might just have to pull the block out if nothing else works. Thanks for the help!