If you're not going to mini tub the car. You might be able to just buy the kit that moves the springs in .75" on each side. This will allow you to run max tire section size of about 10" in the stock fenders providing you get a 7 or 8" rim with proper backspacing to center the wheel between the leaf springs and outer fender.
This modification would be good for a street/drag car but you would most likely experience tire rubbing if your doing a lot of high speed cornering with wide tires. I like it because you are not doing as much cutting and welding.
Or you could go for it and move the springs under the frame and mini tub. That will give you 13" plus for tire section. Not a job for the weak especially on a early Barracuda because of the exposed inner fenders and fold down rear seat.
