This B&M® Shift Improver™ kit fits all 1971-1977 Chrysler, Dodge and Plymouth Torqueflite A727 transmissions, along with A904 transmissions that originally came behind V-8 engines. This kit recalibrates your automatic transmission for optimum performance, extended life by eliminating shift overlap and excess wear on clutches & bands due to slippage. You get two modes of performance to select from: Stage 1 Heavy Duty, or Stage 2 Street/Strip. Stage 1 gives firm positive shifts without loss of driver comfort for improved shifting performance in all street vehicles. Street/Strip is for high performance street use or for competitive events for the enthusiast who wants the hardest hitting, quickest possible shifts. All you need are basic tools, the included installation instructions and in the space of an afternoon you can turn your transmission into a B&M-tuned unit! Ask the thousands of satisfied customers that have installed one in their transmissions!