Not sure which tranny I'm gonna have

Getting a 69 dart gt, automatic and wondered if it's going to be a 727 or a 904. Any reccomendations on a master rebuild kit with a shift kit. I called Jegs and they weren't sure but they priced me a B&M master kit that has a shift kit in it for $239 and a torque convertor for $150. I know they make good products but I know there's enough people out here that have tried out various ones and looking to get opinions on which one works the best.