8. On the left is a semi-metallic, 1.75-inch wide rear brake shoe for small-block V-8 Mustangs. On the right is an organic, 2.00-inch rear shoe for Ford/Mercury intermediates and big-block Mustangs. A semi-metallic lining has bits of metal in the lining and is typically thinner than organic. If you are driving with four-wheel drum brakes, you should use a semi-metallic lining for best performance and longevity. With the right backing plate, drum, and shoes intended for station wagons, you can go up to 2.50-inches in width.