Frequently Asked Questions About Peterbilt 357/378 Elbows, Piping & Comp.

What years do these exhaust elbows and pipes fit on Peterbilt 357 and 378 models?

Our exhaust elbows and piping components are designed to fit Peterbilt 357 models from 1987-2006 and Peterbilt 378 models from 1986-2007. However, specific fitment can vary based on your engine configuration, exhaust system setup, and whether you have a day cab or sleeper. We recommend checking your current exhaust diameter and configuration before ordering, as some models came with 5-inch systems while others used 4-inch or 6-inch setups.

Are these exhaust components made from aluminized or stainless steel, and which should I choose?

We carry both aluminized steel and stainless steel options. Aluminized steel components typically last 3-5 years and cost about 40-50% less than stainless. Stainless steel (usually 409 or 304 grade) resists corrosion better and can last 7-10+ years, making it ideal for trucks operating in harsh weather conditions or coastal areas. If you're keeping your truck long-term or drive in areas with heavy road salt usage, stainless steel provides better value despite the higher upfront cost.

What tools and additional parts do I need for installation?

Basic installation requires a socket set, pipe hangers, and exhaust clamps (if not included). You'll also need high-temperature exhaust sealant for joints. Many drivers find a reciprocating saw helpful for removing old components. Plan for 2-4 hours of installation time depending on your setup. Common additional parts needed include new gaskets, mounting brackets, and flex pipes if your current ones show wear. Having penetrating oil on hand helps with removing rusted bolts from existing components.

How do I know what degree elbow I need - 45, 60, or 90 degrees?

The correct elbow degree depends on your specific exhaust routing and frame rail clearance. Most standard setups use 90-degree elbows for turns at the muffler outlet, while 45 or 60-degree elbows work better for gradual direction changes. Measure the angle of your current elbow or use a protractor at the connection point. If you're unsure, our customer service team can help identify the right angle based on your truck's configuration and photos of your current setup.

Will aftermarket elbows and pipes affect my engine performance or sound?

Quality aftermarket components that match your original pipe diameter won't negatively impact performance. Using the same diameter piping maintains proper exhaust flow and backpressure. However, changing pipe diameter can affect both performance and sound - larger pipes may reduce backpressure but can decrease low-end torque, while smaller pipes might restrict flow at high RPMs. Sound changes are usually minimal unless you're also changing muffler types or adding resonators. Chrome or polished tips don't affect performance but do enhance appearance.