i asked this question long ago when filling mine after a rebuild and got everything from 7-14 quarts. and i ended up over filling it. here's the correct answer i wish i would have got early on.
Automatic Transmission, A727(36RH) Initial Fill..........4.1 quarts
Automatic Transmission, A904(30RH) Initial Fill..........4.1 quarts
Automatic Transmission, Total Fill
3 speed A904(30RH)..........8.6 quarts
3 speed W/O lockup A727(36RH)..........8.6 quarts
3 speed W/ lockup A727(36RH)..........8.4 quarts
maybe a little more for larger trans lines and a large trans cooler.
i have a huge trans cooler, but only an 8 inch coverter, so i'm still about 8-9 quarts. anyone that tells you to put 14 in this thing should help you clean it up off the floor when it comes out the vent tube.