Finetuning questions - do I need a high-stall torque converter ?

This would be a better choice and shoot for around 3200 stall:

http://www.edgeracingconverters.com/904-c-7_8/street-edge-converter-for-chrysler-904-transmissions-p-15.html

Give Andre at Edge Racing a call. He loves to talk Mopars and I am sure he would have a recommendation for you.