It used to be that the notion of an overdrive transmission was absurd to many performance-minded muscle car drivers. Yet as gas prices continue to climb, more and more people are replacing their tired three or four speed manuals for a more modern five or six speed. But as classic muscle cars weren’t designed for these modern transmissions, trying to install one can be quite the headache.

That’s why we are such fans of Keisler’s PerfectFit Transmissions, which we used in our ’71 Nova Project “Swinger.” At PRI 2010, Keisler brought more of their PerfectFit transmissions, which include a new-and-improved case.

Keisler PerfectFit Transmissions are designed for ease of use, with both mechanical and electronic speedometer connections as well as setup for hydraulic or mechanical clutches. There are more than 15 different shifter positions as to fit a variety of vehicles correctly, and the case is designed to be as sleek and narrow as possible. An advanced syncro system features carbon fiber lined double cones that allow for certifiable shifts up to 7,000 RPM. PerfectFit transmissions come in three flavors, rated at 400, 500, and 600 ft-lbs of torque, so not only are they easy to install, but they’re built tough too. It might be just what you need for the next resto-mod project you’re planning.

  • Designed to use stock shifter location
  • Rated up to 600 ft-lbs of torque
  • Setup for electronic or mechanical speedo, hydraulic or mechanical clutch