TREMEC TKX 5-Speed, TREMEC Magnum 6-Speed, and SST's A41 Automatic 4-Speed PerfectFit™ Overdrive Transmission Kits are the simplest and most cost-effective way to convert to a modern overdrive. Silver Sport Transmissions CNC machines the cases and tailhousings of the TREMEC TKX and TREMEC Magnum to streamline them as much as possible. Our compact shifters provide the best fit and shift quality available.

Our PerfectFit™ Conversion Kits come with all the parts necessary to convert your Chrysler, DeSoto, Dodge, Imperial, Plymouth or other Mopar car, truck and street rod into a modern overdrive 5 or 6-speed or 4-speed automatic. Don't just compare our kit prices by the bottom line! Compare each item, you may find other companies have left off some important parts, either because they're not available or come at extra cost. SST is proud to offer the most complete conversion kits available with no fine print.