Transmission questions

Hello y’all, been restoring my volare when I came into an issue where the transmission shit the bed driving it to work a couple months back, this is a 1979 Volare Coupe 318. Now I was wondering how I can find out what transmission it’s running, I’m aware of 3 transmissions in these, I’m looking for a rebuild kit and can only find 727 kits, will these work if I got a 904?
Author: Efful