Hi, when I got my 67 it came with a set of fenders and inner fender wells. I don't know the history of the parts and they are not original to the car. In trying to bolt the inner to the outer they don't match. The fenders seem to fit the body as they should and holes line up. The inner fenders do not line up to the outer fender. Thinking the problem might be with the inner panels I got a new one and the problem is the same. Is it possible that the fenders are Firebird and thus don't fit the inner panel? Or am I missing something . attached a picture of the mismatch I can get the center to bolts in, but then the 2 outside are off a couple inches. and is almost impossible to get the 2 inner or upper bolts lined up. Pictures are with 2 center bolts in to show the mismatch

 

Brain fade, seems to occur more as I get older. It helps to put the right side with the right side and left with the left. Problem was tried to put the Right side together with the left side, so problem now gone. Can't believe I did that .

 

Over 40 Thing happens more than we think.

 

Over 40 was fine, but now over 70.

 

Glad you were able to get your "problem" fixed, it happens to all of us. Good luck on the rebuild.