Well, I've got my NP247 and it looks like a relatively painless swap -- except for the prop shaft. The 247 uses a slip yoke and as far as I can tell no one makes an SYE for it. The 119, from the Eaglepedia, uses a u-joint flange.
I'll see if I can get a good look at mine tonight but I think that's right, so... yeah. Custom prop shaft time. Which sucks, since I'll probably need another custom prop shaft when I get the Ford 8.8" rear end under her. Wish I could wait on the t-case swap but this 119 has gone rapidly downhill.