741 case; 7290 LARGE U-joint yoke???

You might be okay with that case. I took my Dart to the drag strip this year with 323 gears. Launched it all day at 5000 rpm , shifted at 6200 rpm , no problems. they are pretty tuff. I just bought a posi with a 391 gear with the large joint and will try to better my time next time out.