I picked up a 83 s10 and I have a 406 im planning to drop in her.. my question is what do I buy for a rear end ? I know I want posi and possibly 373 or 410 ratio. what do I have and what do I need to buy so everything fits correctly? do I have a 7.5 26 spline? should I get 28 spline if I want to take the truck to the track? what chevys came with 28 spline so I can go to the junk yard ?