My Duster is somewhat similar so you might consider copying my setup. My engine is a low deck 512 with ported Edelbrock heads. It makes right at 600 hp and 600 torque with a hyd roller cam that is 246@050. I use a tight 10 inch converter from Turbo Action. Part number is 17805ST-10. I don't know what the stall speed is but it doesn't slip much at freeway speeds although the slip goes way up when you jump on it. I like how the converter works on the street. It is loose enough that the car doesn't push at stop lights, but it is tight enough that the car moves with only a small amount of throttle opening. If you talk to Paul at TA he will recommend his tight converter for big stroker engines that are street driven.