10-Spline Professional Series GearsSCS 10-Spline Quick Change Gears, Sets #1 thru #28 are Max Lightened, where possible, without sacrificing the strength! Average weight savings 1.5 lbs! Since 1987, SCS Gears have been the proven leader in Ultra High Perf Quick Change Gearing. SCS builds gears that Last! SCS Gears are made of 9310 Aircraft Alloy for max strength. Each gear is Crown Shaved (Ground before Heat Treat) to minimize backlash and run out, broached for proper 10-spine shaft fit and Black Oxide finished. The SCS Extra 5 step heat treating process yields max gear life for high stress applications such as BB Oswego Super Modifieds, World of Outlaw Sprint Cars and IROC Series Cars.