Lets talk stall converters

A tight smaller-body converter is better than a loose larger body. I would go no larger than a ten, and ask for a tight one. Should drive like a stocker and still give 3000+ stall.
It will make a world of difference leaving a stoplight under power. (I'll bet your engine makes 100 hp more at 3200 than it does at 1700.)
I would consider PTC as a supplier too.