IMO for street use and mild cars, and eaton will be fine, and would live a lot longer than a stock unit. However a gear driven unit would outlast as dwayne stated. I do know someone whos' local who has 160K on a stock auburn posi, and it's even behind a 383 and it still works. 3.73s and a posi will easily allow burnouts of the 235/70/15 stock tires
Hell 2.56s one wheel one hell of a burnout.
here's my 2.56 one wheel peel when I test drove my car. 3/4 throttle from a dead stop on newer tires. Car smelled like burnt rubber when I brought it back. Lady never said anything...
GM8 in SPID indicates 2.56s. G80 (rare option on 2.56s) is Posi.
BTW videos in sig..