[Gav]

Very good, not surprising that it wasn't running well after you had the cam fitted it is a different animal from your old one!
Your box will handle alot more than you are asking of it, the 6l80e boxes are based on the old TH400 and will handle what the supercharged engines are capable of.
A stall converter will not turn your car into a pig to drive, if it is bogging down a bit when you mash it from idle the higher stall speed will help it get up to its power band sooner.
I have a 2800 stall, it still has its torque converter lock up and drives very well down low.
Worth a thought if you have the car apart at any point down the track.