Need some help with rear axle position

Info on the internet can be dangerous. Especially Mopar stuff.

Stock A body 8.75's should be 52 5/8" flange to flange. I would drop a string and measure outer fenders lips and calculate where the axle needs to move if you want the tires side to side in their wheelhouses.

These cars were built with horrible tolerances and they stack up. I've had cars where the wheelhouse widths where 1/2" difference.