Description
Overview
The Flowmaster Manifold Downpipe Kit is a purpose-built exhaust upgrade engineered specifically for 1965–1968 Pontiac A-Body vehicles equipped with a 389 or 400 cubic-inch Pontiac engine. Sold as a matched pair in a dual configuration, these manifold downpipes replace the tired factory pipes with a clean, precisely fabricated set designed to bolt into the original locations and restore proper exhaust flow off the manifolds.
Each downpipe is manufactured from 2.50-inch mandrel-bent 409S stainless steel tubing, a material chosen for its strength and corrosion resistance. The mandrel bends maintain a consistent 2.50-inch diameter through every curve, preserving smooth, unrestricted flow where cheaper crush-bent pipes would pinch and choke the exhaust. High-quality flanges and the included factory-style 2-bolt flanges make for a tight, dependable connection to your manifold castings.
Key Benefits
Reproducing the correct downpipe geometry for the Pontiac A-Body platform means you get a proper fit without fabrication guesswork. The natural stainless finish, mandrel-bent construction, and 409S material combine to deliver a durable foundation for the rest of your exhaust system. With a 2.25-inch inlet feeding into 2.50-inch main piping, these downpipes are sized to work with your Pontiac’s manifolds and carry exhaust rearward efficiently.
- Mandrel-bent 2.50-inch 409S stainless steel tubing for smooth flow and long service life
- Sold as a complete pair in a dual system configuration
- Includes factory-style 2-bolt flanges for a direct, secure connection
- 2.25-inch inlet and 2.50-inch outlet / main piping diameter
- Natural stainless finish
- Backed by Flowmaster’s Lifetime Limited Warranty
Fitment
These manifold downpipes are designed for all 1965–1968 Pontiac A-Body vehicles running a 389 or 400 c.i. Pontiac engine. They fit only with manifold castings 9779032-D/S and 9779328-P/S, so confirm your casting numbers before ordering to ensure a correct match. This kit is configured for 2WD applications and falls under Emission Code 3.
Why Choose Flowmaster
Flowmaster’s reputation is built on well-engineered exhaust components, and this downpipe kit reflects that with quality stainless construction and precise, application-specific design. Whether you’re restoring a classic Pontiac A-Body to its original character or building a fresh exhaust system from the manifolds back, these downpipes give you a solid, corrosion-resistant starting point. The included factory 2-bolt flanges and no-compromise 409S tubing make installation straightforward and the results dependable.
Warning: This product carries a California Proposition 65 warning. A heat shield is not included with this kit.
