I have a TCI Super Streetfighter converter behind my C6. It stalls around the advertised figure of 3600 rpm behind my 428. TCI doesn't have the best reputation, but I bought this converter used for $45, believe it or not. So I tried it. I would say it works really well. I street drive it and run mid 11's in street trim.
However, if I were to get a new converter today, I would get one made by Broader Performance or by ATI.
JMO,
paulie