Sounds like the guy up the street has a spool--solidly connects both axles with no slippage in turns, more of a drag race only deal, not good on the street. The 10 bolt GM had a limited slip differential available, think there's a couple different ones in it depends on which axle housing you have, maybe some GM guys will chip in on that... There are a number of aftermarket companies offering limited slip rears for a 10 bolt. For street use and maybe an occasional blast at the track might want to check and see what Auburn has available. A 10 bolt isn't the strongest rear end on the market, but in something as light as a T Bucket it should hold up ok with a limited slip installed.