Biggest 15" front tire for my barracuda

It depends on your rim. For example I have 225-60-15 BFG TAs on the front of my 65 Formula S. Torsion bars are stock .870s cranked down for approx a 1" drop in ride height (rear lowered also). Rims are 15x7 with 4.25" of back space, same as the"cop" rim (rear is 245-60-15s on same rim). I have zero rub any where. A deeper back space will allow you to run a wider rim/tire combo, ultimately limited by upper ball joint/tie rod end interference, over a stock spec. rim. If your running stock rim dimensions then stick with above recommendations. I think you would be safe in just about any A body with my tire/rim dimensions in the front.