Where is the weak point

I don't see why it wouldn't. I've never taken one apart either, but will give it a go soon, for my own 65 Barracuda. I do know that there are 2 different A body tail shafts. Early (66-67) ones use a 904 size slip yoke and later ones use the 727 size slip yoke. @Dan Brewer can tell you each and every part you'd need to swap it out, and can supply it to.