i like to start off with 79-80 front axle without the tuss on the bottom   that give you a lil clearance than 81-85 . i just gusset the ball knuckle part . 
i have ran stock birfs locked front and rear  for acouple years and haven't  break a birf yet  but my friend on the other hand broke his birf everytime we are out . we have same style of driving the only different is his truck is lil heavier