swapping 727 guts

i’m wanting to swap the guts out of my small block racing tranny into a big block casing, are all the casings pretty much the same, and the guts will fit, or does it have to be year specific??

i'm wanting to swap the guts out of my small block racing tranny into a big block casing, are all the casings pretty much the same, and the guts will fit, or does it have to be year specific??