gear oil.

OK so what should i run for a street car running 3.91, in the past i have been running Valvoline 85-140, should i change?? I havent had any problems with it but this duster will see a little more RPM than my other cars and trucks. Also what grade and type for the A833 tranny its bone dry and I am not real sure of the grade to run in it??Evrything has had a freshe rebuild.