Ok, that's news to me on the bolt pattern. I guess they've been upgraded then as I'm almost certain they are 4.5. I don't know the gear ratio as the rear was in the car when my dad got it. It will run 65 comfortably on the highway. I'm in Oklahoma City. I'm not sure about the manifolds. If there's a casting number I can get for you or a closer photo, let me know.