2. For added strength, each bracket is CNC machined out of 3/8-inch steel plate. The supplied hardware features cad plated 3/8-inch Grade 5 hex bolts with nyloc nuts that mount onto the motor mounts. The three additional metric flat head cap screws are used to mount the bracket onto the engine block itself. Once the motor mount is attached to the brackets, this is what allows the motor to be moved back and forth for final fitment.