Rear tires not centered in wheel well

That's how mine was on my 67 barracuda.
I could not add a spacer due to the spring relocation and mini tubb so I had to massage the forward wheel opening 1.5 inches.
I had my buddy do it that knows his way around sheet metal work.

If you did not relocate the springs you should be able to add a spacer to the front stock mounting location.

Before and after pics.