If the rearend is original, have you considered a different torque converter? You never have to admit it and it can definitely help low speed acceleration. Don't get carried away, a 2000 RPM converter will be inexpensive and really help. Probably less work than going through the rearend anyway. If you are going to a higher speed converter, DO NOT forget that there will be additional heat load at the transmission, especially at low vehicle speeds--adding an aftermarket trans cooler is always a benefit for transmission durability and lifespan. Dave