with only 1 ft torque diffence I think I would run a 6800- 7000 stall as at 7000 it makes 637.5 ft torque and peek is 638.8 at 7100
You have plenty of gear to let it climb into its max torque quik enough .
It is hard to build a loose convertor that does not slip in top gear.

Quote:


Based on that dyno sheet you would like that 7400 stall...
at 8000 stall you would be a long way past peak torque