These Ram 10 lb. racing flywheels are made of billet steel, not a cast stock piece cut down. Will work with 10.5" B&B or diaphram style pressure plates. These flywheels MUST use a solid hub friction plate (sprung hubs will not clear).
Note: This flywheel requires very short bolts for mounting, as it is very 'thin' in the center. Use ARP flexplate bolts # 101-2002902.