The Keisler PerfectFit" System is the easiest and most complete way to put a high strength, modern overdrive Tremec TKO or T45RS 5-speed transmission in your 1964.5-1970 Mustang or 1967-1970 Cougar. Our Keisler Custom Engineered PerfectShift" Tailhousings and Shift Mechanisms provide the smoothest operation, the shortest throws and the only true internal offset in the business. Enjoy a PerfectFit transmission with low RPM cruising, and great fuel economy today.

The Keisler ClassicFit" Kit is the most economical way to put a high strength, modern overdrive Tremec TKO 5-speed in your Mustang. Our ClassicFit" Kits contain all the same high-quality components as our PerfectFit systems, but with an unmodified transmission. Enjoy a 5-Speed System with low RPM cruising, and great fuel economy today.

NEW!  Keisler ClassicFit™ Offset Shifter is now available! It provides the same correct shift lever attachment point as our premium PerfectFit™ series, but in a lower cost "bolt on" package. Modification of the 4-speed shifter hole is required for some applications. (Note: If you desire a little-to-no mod installation, please see our PerfectFit™ series of transmission systems).

Bare TREMEC transmissions - Contact us for the best price on bare units and Essentials kits for TKO & T45RS.

Keisler Engineering offers a wide range of products to choose from to make your pride and joy into the masterpiece you've always wanted. Click 'Select' below to show accessory categories for your vehicle.