Got my 6" lift installed on my truck and the front driveshaft is too short and has too much angle. So much angle it wont even turn. It has the cv joint at the top and it doesn't have enough flex. The shaft in fairly new(about 1 year) and is in great shape. Can I grind some off of the ears on the u-joints at the cv joint? The ears have a square corner on them that makes them hit the center piece of the the cv joint. I don't think its going to affect the strenght, but are the squares on there to prevent them from flexing too much?

Yes you can grind it. It's called a clearance grind and is usually required on truck with more than 8" of lift. Just grind out the little squares and you may have to grind some of the yokes as wel. Take your time and pay attention to the ujoint bolt clearance too. Just because the yoke turs freely outside of the truck doesn't mean it will when you put it back in.

the problem is you have the shitty long body cv with a flnge base, if you hit the junk yards you can find the short cv with the yoke base. it will give you a longer shaft with more flex.

You could also swap in the offset u-joints to get the clearance you need, on a front shaft the vibes wouldn't be a problem, I forget the name, but its just a u-joint with the crosses offset so it clears at a higher angle.

you cant use an off set u joint on a cv, which is where he needs the extra movent.

I took an angle grinder to the square corners on the u-joints and it clears fine now, no binding at all. Now I just have to get it stretched out about 2 more inches.