Unless you drive it with a light foot, a decent V8 is going to put the axles on borrowed time, especially the notoriously weak-kneed Dana 35 rear axle. But then again, if you drive it with a light foot, there's no point in swapping to a V8 in the first place. Bottom line is, the trans, d-shafts, and at minimum the rear axle will need to be replaced. The NP231 transfer case can be kept, although I'd recommend rebuilding it with a wide chain kit, 6 pinion planetary and a SYE kit. These upgrades will beef it up to V8 level specs.
I have a Dana 44 rear axle with a new in the box disc brake kit for sale, if you're interested. I was planning on using it for my Wrangler, but in the 11th hour, decided to go with a 1 ton axle.