There are so many variables that it is impossible to give a decent answer to this one. No converter expert here, but It sounds like the driveability "feel" is as important to you as all out performance, which it should be with a street strip car. You may be more satisfied with a matched smaller duration cam/tighter converter combo. How much duration do you now have, and where does to torque start to come in?
with 540 cubes, a STOCK stall range 426 Hemi converter is a good fit if built strong enough to handle the torque. It will probably stall minimum 3400 rpm. They won't live without some improvements though,AMHIK. Mine lasted six passes behind a 535, 3600+ stall out of that stock factory 10 3/4 converter.