Close vs. Wide RatioWhich Top Loader transmission should you chose, close or wide ratio, and why? Close-ratio is centered mostly around quick acceleration, which is why you'll find them in the Boss 302, Shelbys, and other high-performance applications. Wide-ratio makes more sense for open-road driving.
Gear ratio boils down to how many revolutions the input shaft turns versus how many revolutions the output shaft turns in a specific gear. For example, if we have a First-gear ratio of 2.78:1 in a wide-ratio box, that means the input shaft turns 2.78 revolutions for every one revolution of the output shaft.
How do you identify close- or wide-ratio? Although we want to trust the identification tag, that's not always possible because many of these older transmissions have been rebuilt in the past. In some cases, close-ratio transmissions have been converted to wide-ratio and vice versa. In fact, we're taking a wide-ratio box and turning it into close-ratio for racing purposes. When you want to be certain, pop the top cover and count the gear teeth.