camokrawler said:
i had 38x16r15 and drove the piss out of it and only broke a u joint with open diffs and 4.10s
It doesnt sound like your wheeling it hard. Give us some specifics here. What kind of wheeling do you do? If its only street driven then you arent going to break u-joints all the time, but in my opinion it is unsafe with 1/2 tons. I wouldnt even think of taking 44's and half tons out on the trail.

Thats just scary!!!! If you snap a rear shaft on a hillclimb (very very very very very very very possible with 44's on 1/2 tons) your tire will fall off and you could roll! I, and im sure everyone else on here, is gonna tell you that it is not safe to drive with 1/2 tons on 44's. I wouldnt even ride in that truck.
To answer your question, where did you get the headers from? It could be possible that you ordered the wrong ones or were sent the wrong ones. I would suggest talking to the place you bought them from. If not, you could always plug the holes up with a threaded plug.
And to answer your other question, you wont have good flex with 12" of lift. The larger the lift, the more the spring comany has to arch the spring. The more arch a spring has, the less it will flex and it will ride like crap. Generally anything over 6" is seriously limiting flex. You can run 44's on 6" if you just hack the fenders. Why go 12" if your looking for flex? Anything that is going to require a large amount of flex, 44's, and front and rear lockers is gonna snap those 1/2 tons before you even get your foot on the gas.
BTW-I am not trying to be a jerk by telling you that your 1/2 tons are unsafe with 44's. Im honestly trying to help you save your truck, and yourself from injury. 1/2 tons are not suitable for 44's. period. My friend broke his half ton rear shaft on 35's just crossing a small (maybe 2 feet deep) ditch at school (doesnt even require 4wd, and stock cherokees easily made it through), and his tire fell off 1 block away when he was doing 45 mph.

That is scary. And that is what WILL happen if you even look at driving off pavement (and maybe even on) with 1/2 tons and 44's.
Oh-And with the money it takes to stuff detroits, 5.13's, and chromo's in your half tons, you could easily find a 14ff rear, and d60 front. Then wait on lockers. You can get alot farther open front and rear on 1 tons, then locked front and rear on half tons with broken shafts and u-joints. You will thank yourself in the long run.
-Harrison