Diff gear recommendations
Keep the 323's and get a 3500 stall converter. . It will drive normal and kick *** power on acceleration. I went from 323's - 355's -391's -410's still had a hard time spinning a set of factory size tires riding the brake.
I installed a cheap 3500 GER converter and went right back to 323's . It torches the tires from a throttle stab with no brake.
All the 340 cars I bought in the 70's brake stalled at 2800- 3000 if they had a factory 340 converter. Put that same converter behind a 383 or 440 and it brake stalled at 3300 -3500. I did it many times on many different cars.
I had one RR that had a chrysler New Yorker trans put in. That converter turned the car into a real pooch. Back in the 80's the turbo action XX was the replacement for 340 and Hemi. advertised stall 3000- 3500
Believe me skip the gear change and get a converter. What trans do you have a 727 or 904 and what year?