modifing the lower control arms

[Truckhead]

I have a 4/6 drop kit and a disc brake conversion from ECE on my 70' sb fleet and i'm running 16 inch rims. The problem i'm having is the inside rim lip is rubbing the control arm. Well, i ground some of the arm away but it still rubs at almost full turn lock.
What do you guys think about notching the control arm on both sides and then boxing the arm in? Is there an aftermarket lower control arm i can buy instead that will have the clearance for my rims? I got to do something as i went in for the frontend alignment and found also that my lower ball joints were damaged upon install(it looks like the shop that did the install beat the ball joints in with a hammer) resulting in quirky steering problems. With the truck on a lift it takes alot of force just to turn the tires left or right pushing on the tire, very stiff. So i figure i'll fix 2 problems at once.