Porsche 911 After-Cat Exhaust System

We started from scratch to offer a complete high performance exhaust system for the Porsche 911. Extensive dyno testing on our in-house dynamometer afforded us impressive horsepower and torque gains throughout the entire power band. Headers and muffler are meticulously built by hand using T304 Stainless Steel for a lifetime of performance - guaranteed!

Using the highest quality stainless-steel these after-cat exhaust systems were constructed for the Porsche 911. Available in both single and dual-exit exhaust systems, and with choice of different size and style exhaust tips, the choices Billy Boat affords with its systems allows for fantastic customization of any Porsche 911. All of this makes for a 911 modification that is both incredibly stylish and functional.

The kit for the naturally aspirated Porsche 911 includes all necessary hardware, gaskets and accessroies needed for a complete installation. Factory-fit, cat-inlet mufflers are also available in a wide variety of applications and configurations with your choice of tips.

Please Use the chart below to decide which after-cat system is best suited for your Porsche 911 Application and choices:

Model Porsche	Headers	Exhaust Outlet	Part #
1975-83 Porsche 911	Stock Headers	Single 3” Oval	FPOR-4200
1975-83 Porsche 911	Stock Headers	Single 4.5” Oval	FPOR-4205
1975-83 Porsche 911	Stock Headers	Twin 3” Oval	FPOR-4210
1975-83 Porsche 911	Stock Headers	Twin 4.5” Oval	FPOR-4215
1984-89 Porsche 911	Stock Headers	Single 3” Oval	FPOR-4300
1984-89 Porsche 911	Stock Headers	Single 4.5” Oval	FPOR-4305
1984-89 Porsche 911	Stock Headers	Twin 3” Oval	FPOR-4310
1984-89 Porsche 911	Stock Headers	Twin 4.5” Oval	FPOR-4315
1975-89 Porsche 911	B&B Headers	Single 3” Oval	FPOR-0450
1975-89 Porsche 911	B&B Headers	Single 4.5” Oval	FPOR-0455
1975-89 Porsche 911	B&B Headers	Twin 3” Oval	FPOR-0460
1975-89 Porsche 911	B&B Headers	Twin 4.5” Oval	FPOR-0465