tru trac or locker
There were two types of sure grips. Early ones were power locks with the 4 spider gears and two shafts like the early clutch type 8 3/4 diffs. Those are really strong and should hold up with your new combo. The later trac lock type have only two spider gears on one shaft and are prone to cracking under heavy loads. Hence the nickname "crack lock" As far sd the trutrack goes I have heard nothing but good things about them and would buy one over the locker. I have a power lock right now and if it ever breaks which is doubtful I will go trutrack.