My old converter was a Dynamic and worked pretty well, but was a bit loose on the street and Highway.
I spoke to Ultimate and told them I had a 4,150 # Charger with 3.91:1 gears and a 500" stroker making over 600+ HP, but wanted a converter that does not slip much on the street. They built a custom 9" converter that is great on the street (feels pretty tight and dies not seem to slip much at light throttle), and will flash to 5,000 when I go WOT. So I'm a Happy customer even though the converter was kind of expensive.