converting an 8 3/4 to the correct sure-grip

Hey Frank, You've come to the right place. "The straight scoop"? I dont think so. "Obsolete" ? What rock did this guy crawl out from under? I'll bet he has something he can order for you that's a lot better. Randy's Ring and Pinion is where i shop. There are some after market units out there that work very well but dont be afraid of the "obsolete" units either. Good luck with your project.
Small Block