So I've decided to "go big or go home", and do a full with axle swap, but I've already found myself lost with these things called " manual locking hubs", not really an XJ thing lol. So what I've got is a 78' ford dana 44, and I've changed the outers to the heavy duty, external mount hubs, but what my question is, is what spline hubs do I need with the heavy duty outers and are they compatible with what I already have?????? Please help!!

 

Unless you got upgraded shafts they will be 19 spline. I'm running chromos in mine and they are still 19. Welcome to the club, I'm running a 78 F250 44 front as well.