Our PerfectFit™ Overdrive Transmission Kits are the simplest and most cost-effective way to modernize your vehicle. Whether you prefer the precision of a TREMEC TKX, T-5, or TR-4050 5-Speed, the high-performance Magnum, Magnum-F, or Magnum XL 6-Speed, or the smooth operation of Silver Sport Transmissions' A41 and A41X Automatic 4-Speeds (based on the 4L60E), we have the engineered solution for your build.

The Most Complete Kits on the Market

• Engineered Variety: Choose from world-class TREMEC manuals or our proprietary SST A41/A41X automatic 4L60E-based overdrives.
• No Hidden Costs: Compare our kits piece-by-piece; we include the essential components other companies leave out.
• PerfectFit™ Technology: Designed to fit your specific floor pan with minimal to no modifications for a factory-clean look.
• Modern Driveability: Drastically reduce highway RPMs, improve fuel economy, and enjoy a quieter, more refined cruising experience.

SST is proud to offer the most comprehensive conversion kits available with no fine print. Whether you are looking for a TREMEC manual or a 4L60E-based automatic, don't just compare the bottom line—invest in a complete system backed by expert support.