What transmission you running? And what size(diameter) converter is your 3200? I have seen a few people go from a 3600 to a 4000 and drop .15 and pick up mph.

I think it also depends on your power band..where is your peak power? and how far does it carry power past 6300rpms? IMO a big converter needs a cam that wants to make power to 6500 to keep the truck pulling.