I'm in the process of ordering a new complete 3rd member for my 30spline 8 3/4" and my question is what should I order? The vehicle is a 69 Roadrunner with a 500hp 440 backed up by a 5 speed manual transmission. This is a street car with 275 60 R15 BFG's and it will see no tracktime. In my other cars I have always used a Detroit Locker and I'm happy with that but I'm curious  about the Eaton true track and Doctor Diff's Helical Gear Sure-Grip ("Sure-trac II")
Please advise me.