Peterbilt 359 DPF & Mufflers

Frequently Asked Questions About Peterbilt 359 DPF & Mufflers

Will these mufflers fit my specific year Peterbilt 359?

Most aftermarket mufflers for the Peterbilt 359 are designed to fit models from 1967-1987, which covers the entire production run. However, mounting brackets and pipe diameters can vary between early models (1967-1979) and later models (1980-1987). Always verify your exhaust pipe diameter before ordering - standard sizes are typically 5" or 6". If you have a custom exhaust setup or modified truck, measure your current system to ensure proper fitment.

What's the difference between chrome and aluminized steel mufflers?

Chrome mufflers offer superior corrosion resistance and maintain their mirror finish longer, typically lasting 5-7 years with proper care. They're ideal for show trucks or drivers in harsh weather conditions. Aluminized steel mufflers cost about 40-60% less than chrome but may show surface rust after 2-3 years, especially in salt-heavy regions. Both materials provide the same sound performance and flow characteristics - the choice comes down to appearance longevity and budget.

Do I need special tools or professional installation for these mufflers?

Basic muffler replacement typically requires standard hand tools including wrenches, a reciprocating saw or pipe cutter, and clamps. Most installations take 2-4 hours for someone with moderate mechanical experience. The main challenges include removing rusted bolts and ensuring proper alignment. Professional installation usually costs $150-300 but guarantees proper fitment and may include warranty coverage. If your exhaust system needs extensive modifications or welding, professional installation is recommended.

How do straight-through mufflers compare to chambered designs for the 359?

Straight-through (glasspack) mufflers provide maximum exhaust flow and a louder, more aggressive sound - typically 3-5 dB louder than chambered designs. They're preferred for performance applications but may drone at highway speeds. Chambered mufflers offer a deeper, more refined tone with better sound control at cruising speeds while still maintaining good flow characteristics. Neither style significantly impacts fuel economy, but straight-through designs may provide 1-2% better flow in high-performance applications.

What about DPF systems for older Peterbilt 359 trucks?

Original Peterbilt 359 trucks (1967-1987) were manufactured before DPF requirements and don't need diesel particulate filters unless you're retrofitting for specific state regulations or company requirements. Retrofit DPF systems are available but require significant exhaust modifications, ECM programming, and typically cost $3,000-5,000 installed. Most 359 owners maintain original exhaust configurations unless required by law. Check your local and state regulations before modifying your exhaust system, as requirements vary significantly by region.