2:73 Gears In An E Body Rearend?

Your post doesn't make too much sense . 904 is usually in reference to an automatic transmission ? If you're meaning a 9 1/4" or 8 3/4" axle that would make more sense. Your question of whether or not dart axles would work would depend on whether or not the axle housing was narrowed to fit under
an a-body . If so than yes a stock a-body axle should fit with the correct brake hardware . If not than no a standard a-body axle would be too short.
Yes people have put wider b/e body axles under a-bodys .