the d44/9 will be strong enough considering there run on v8 bronco i have a front d44 with chromolies and longfield ujoints with 37s on my 4runner and haven't broken anything on it since i swapped it in back in 04 but im am also not heavy on the gas when im wheeling
I guess that really depends on the terrain you wheel. Here in AZ, we wheel non-stop waterfalls, deep notches, and boulder fields with endless undercuts. I've destroyed 30 spline Longs, chromo Toy rear shafts, Toy R&P's, countless D44 chromo shafts, joints, and R&P's, D60 chromos and joints, and 14B shafts. I've also broken a D60 housing in half and I don't consider myself "hard on the gas" when I'm wheeling either. It's just part of the terrain here, everyone who actually wheels has carnage unless they're running "the bunny trails". My point is that if I were going to spend the time, effort, and money to do a swap...it wouldn't be for those axles that are marginally stronger than "built" Toys. .02
If the point of the swap is because full width "looks cool at the mall" and won't really be wheeled very hard...go for it. I don't know where or what terrain the OP wheels, so just giving advice from my personal experiences.
