Shifting at 4600 rpm?

Trying to get all the kinks worked out since dropping in the 383. Kickdown is adjusted and working great and I'm getting full throttle with the pedal but when i take off keeping the pedal on the floor the car will shift around 4600. It seems awful low for a 383 and was just wondering if I missed something?? Is there something in the tranny that could be holding me back?
Author: 71DartGuy