These Ram 10 lb. racing flywheels are made of billet steel, not a cast stock piece cut down. Will work with 10.5" B and 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 # 101-2002906. Item Details Ext. Balance Clutches, Flywheels and release bearings are STRICTLY FACTORY WARRANTY ONLY. Customer must return the unit to RAM for evaluation and inspection. For a full list of warranty information please see our warranty information here