Step By Step
As you can see here, the Thorley header is much longer than the stock exhaust manifold. This length, combined with the Tri-Y design, is said to allow these headers to produce more torque and horsepower at lower rpm than the stock exhaust.
The stock exhaust headers are designed to fit within the frame, but the amount of power they can help produce is limited. (Note: for visibility reasons, these photos were taken with the front sheetmetal off the truck.)
Installing headers is a simple task. All you do is remove your stock headers and install the new ones in their place. We measured how far the headers extended back and cut the exhaust pipes off at an appropriate point. Later, we had common muffler flanges welded to the exhaust pipes, and bolted them to the header. Be sure to use header bolts to install your headers. The smaller heads of these bolts make installation much easier.
The Thorley Tri-Y headers fit into the frame with little room to spare.
Here is a view of the headers from the underside of the truck. This application has a TH-400 automatic transmission, but we found that these headers also fit perfectly with a manual tranny. Now the only thing left to do was connect the exhaust pipes to the headers.
Exhaust flanges like these are what a shop will use to connect your exhaust pipes to the headers. These pieces are welded to the ends of your exhaust pipe and are then bolted to the headers. A gasket seals the connection.
In the early days of motorsports, gearheads discovered that a free-flowing exhaust allowed an engine to produce more power than was possible with restrictive stock exhaust manifolds. Over the years, headers have been refined and improved to the point that they arent just for racing. Everyone can benefit from a well-built header.
Corona, CA 92880