[o6r1man]

I've never tried synthetic in the rear end before, I have always ran regular 80/90 and my el camino with the 496 in it runs mid 10s hanging the wheels a little bit off the line. The ring and pinion in it is 18 year old Richmond street gears in it. I do run Mobil one oil in all my stuff except my duramax and I just run regular rotella in it. I'm on my 3rd new dmax and always ran rotella with no problems..