My bellhousing was already removed and the bolts long gone when I got the project. Wanted to bounce this off someone who has done it before. Mounting my 304 to the engine stand bracket. The two 7/16-14 bolts at the bottom corners thread in fine. The top two 3/8-16 bolts go in about quarter inch and the become extremely hard to turn, mangling the threads on grade 8 bolts. They aren’t bottoming out by a long shot before this happens. Seems to be all four of the 3/8 holes when I test the others. Is this normal or could the bolts be a different thread? Don’t want to force it and cause damage. 1972.