If its not adjusted right id drive my *** back to whomever did that ****. But to answer your question, not really. You can grind a weld down, if its slip fit and then welded, and have minimal header damage, but if its buttwelded or slipfit with deep penetration its gonna mess up the header collector (granted not much, only as far as the weld is wide, which isnt wide), but considering your gonna be under the car doing this...Id make them fix there stupid mistake (the banging) and drill them for their dumbass decision.