3:73 Rear End

When it comes to muscle cars and powerful vehicles, one component that is always in the conversation is the rear end. Specifically, the gear ratio of the rear end can have a significant impact on the performance of the vehicle. One gear ratio that stands out in the world of muscle cars is 3:73. In this article, we will delve into what a 3:73 rear end is and what impact it can have on your vehicle’s performance.

What is a 3:73 Rear End?

Firstly, let’s understand what a rear end is when talking about cars. A rear end, also known as the differential, is the component that sits between the rear wheels of a car’s axle. The purpose of the rear end is to allow the wheels to rotate at different speeds during turns while the engine and transmission remain constant.

A 3:73 rear end refers to a particular gear ratio between the ring and pinion gears in the differential. The ratio signifies that for every three turns of the driveshaft, the wheels will turn 73 times. This is a more aggressive gear ratio than others typically found in vehicles, such as a 3:23 or a 3:42.

Impact on Performance

So, why would someone choose a 3:73 gear ratio for their vehicle? The answer lies in the impact on performance. With a 3:73 rear end, the vehicle will accelerate faster from a stop, as the gears provide more torque to the wheels. This increased torque also benefits the vehicle in situations where quick acceleration is required, such as passing on the highway or merging onto a freeway.

However, the 3:73 gear ratio does come with some trade-offs. For one, the vehicle’s top speed will be lower compared to other gear ratios. The engine will also be revving at a higher RPM while cruising at highway speeds, leading to decreased fuel efficiency. Additionally, the vehicle may have a louder, more aggressive exhaust tone due to the higher RPMs.

Compatibility with your Vehicle

It’s important to note that not all vehicles are compatible with a 3:73 gear ratio. The vehicle’s transmission, engine, and tire size all play a role in determining what gear ratio is appropriate. It’s recommended to consult with a mechanic or a specialist to determine if a 3:73 rear end is suitable for your vehicle.

Installation and Cost

If you do decide to upgrade to a 3:73 rear end, the installation process can be complicated and time-consuming. It’s recommended to have a professional mechanic handle the installation, as it involves removing the entire rear end from the vehicle and replacing the ring and pinion gears.

The cost of upgrading to a 3:73 gear ratio can vary depending on the vehicle and the mechanic’s fees. Expect to pay in the range of $800 to $1500 for the cost of new parts and installation.


In summary, a 3:73 rear end can offer significant benefits to a vehicle’s performance, such as improved acceleration and torque. However, it’s crucial to consider the trade-offs, such as decreased fuel efficiency and a lower top speed. It’s important to consult with a professional mechanic to determine if a 3:73 gear ratio is suitable for your vehicle and to handle the installation process. With the right setup, a 3:73 rear end can provide a thrilling driving experience for any muscle car or performance vehicle enthusiast.