Stall?

It ain't rocket surgery.. Stock converters are far from junk; lasting hundreds of thousands of miles. It's funny, the same guys who tell ya to fork out $600 for a converter will swear by a 904 behind 450hp. fuggetaboudit.
No, it is not rocket surgery, it is hydraulic science/engineering. Stock converters are not junk, for stock or extremely mild engines. Speaking of stock converters, do you know how many different non lockup converters Mopar had? There were many, based on the engine torque, and vehicle weight, and gear ratio. The OP doesn't need a high dollar race converter, but he should invest in a decent converter matched to his engine/car. Otherwise he is leaving performance on the table.
PS: It doesn't cost a thing to make some phone calls, and get the info from the horses mouth. Then the OP can make an informed decision. If you notice, I did not recommend any size/stall for a converter, or even a particular company. I essentially Just steered him away from advertising hype, and to people that have the expertise to give him good advice.