Is there such a thing as a 5000 stall converter that is streetable ?

The days of using a stock Vega or Opal converter are long gone. The converters are now internally modified to do what they do.
I had a Vega converter behind a 327/350 hp SBC in the late 70's. I didn't know enough to put a transmission cooler on it. Smoked the trans and converter in a few days. Made a big difference though.