01. Ceramic-coated headers are from Street & Performance.
02. Header collector with O2 and exhaust temperature units installed.
03. Ken Kleitz of Patten Cycles taking system measurements.
04. Driver-side exhaust pipe.
05. Exhaust hanger at transmission crossmember.
In our project series thus far, we've covered project planning, chassis, suspension, drivetrain, braking, and installing C5 seats in a midyear. In this installment, we'll address three aspects that will consume quite a bit of your time. These are the various engine-related systems, such as engine electronics, exhaust, fuel, and cooling. In this installment, we'll cover the first three of these and address the cooling system in a future article. Over the course of this project series, we'll cover each one in enough detail to give you a good idea of what's involved and the sources we used. Since each project is unique, and you'll have your own ideas on the approach to take and components to use, we'll just describe the approach we've taken, and what has worked for us.
Exhaust System-Key Design FactorsThe key factors to consider in the design of your exhaust system are clearance, performance, and routing.
Clearance: Adequate space for clearing the body and other components and allowing enough room for the heat generated are key aspects to consider in your design and choice of components. In some instances, it may be possible to use stock exhaust components; however, in many cases you'll be faced with having your exhaust pipes custom bent or, at least, modifying some of the system. For our project, we decided to build a complete system in stainless with custom headers, exhaust pipes, mufflers, hangers, and exhaust tips. We'll describe the design and show the system's design a little later.
PerformanceHeaders: Depending on your objectives, and whether you want to achieve maximum engine output, you may decide to use headers in either the short- or long-tube design versus stock manifolds. The size of the primary tubes is also a factor and should be matched to your particular engine. There are many sources today for LS headers, such as Street & Performance, Sanderson, Stainless Works, and so on that should have headers which will fit most of the custom Vette-Rod chassis. Quite often stock manifolds will also fit and can have the advantage of being quieter. For our project, we worked with Street & Performance to develop headers to match the unique exhaust port shape of the LS7, have the right sized primaries, and clear the engine and framerails. We also chose to use Stage 8 header and collector bolts that have a lock to keep them tight (Photo 01).
Coating: Ceramic-coated headers are a good choice as they retain their appearance, as well as keep the underhood temperature down. Typically, the claims for heat reduction are in the range of 60 percent on the header surface as well as increased exhaust scavenging. Many companies coat both the outside and the inside of the header.
Exhaust & Tailpipes Material: We like to use 304 stainless for our systems as it lasts forever, retains its appearance, and can be polished if you want to take things that far. We also use stainless collectors for the headers and weld the exhaust pipe directly to them. Photo 02 shows the collector thathouses the O2 sensor. The second bung you'll see is for the probe to measure exhaust temperature for a gauge mounted in the dash.