We were able to get 39xx, sometimes 4000 rpm out of a 1053-1 last year every run. 4th gear start, 4.56 gears. The 1055 from year before would get 3600 but would couple so hard that the charger wouldn't come to life. Suncoast definitely makes great converters and it's cool to see the stall & coupling differences when switching models.
I found it strange it stalls and couples hard at the same rpm(1900).From what i gather thats prob my issue or part of it.4k from any converter is impressive.Thanks for sharing guy's!