It's ALL about the stator and pump fin angle. The stator in the new converter is much more aggressive, as shown by reduced slip, lower rpm and mph at the stripe. Once the converter welds itself to the motor, you simply don't have enough grunt to pull it up top. You probably lost most of your ET and momentum at the 330. Check to see if it is running the backhalf the same. If you have more, turn the wick up after the 60ft and make it run to 330 and it should be quicker.

WAY more to a converter than where it stalls

The converter doesn't know if it's a small motor or a big motor, nor does it care if it's a Mopar, Ford or Chevy. It simply knows torque