[ss3011]

K=R/square root of T

K is the constant Factor of the converter and will stay the same
T is torque
R is the stall speed

So by combining old torque equation and new torque equation , knowing K is constant

Rnew = Rold x (SqRt Tnew / SqRt Told)

Example
Rold = 5000 rpm
Told = 500 ft.lbs.
Tnew = 550 ft.lbs.

Rnew = 5000 x (sqrt 550 / sqrt 500)
Rnew = 5000 x (23.45 / 22.36)
Rnew = 5000 x (1.0488)
Rnew = 5244

So basically with this converter if you upped the torque by 50 ft.lbs , it would increase the stall from 5000 rpm to 5244 rpm .