ZoomieSBC Header Set, Small Block Chevy

Dimensions

Zoomie Length

Most Zoomie headers are offered in two lengths, either a standard 16″ (40.64 cm) or a longer 19″ (48.26 cm). (Big block Chevy Zoomie headers are a specific style and only one length). It is relatively easy to determine the length needed for the application. To be clear, 99% of all applications will use the standard 16″ length. The longer 19″ version requires a much higher chassis or engine location to allow necessary ground clearance.

To provide a simple example, the header should not hang down below the bottom of the wheel. However, this will vary depending on the wheel and tire profile. In the graphic below, a low-profile tire provides less ground clearance; therefore, the bottom of the header should maintain a higher value from the ground.

Many like to have that scraping-the-ground look on their street rods. However, that sort of look is best suited for trailered show vehicles and not those expected to travel city streets, including driveways, v-drains or dips, speed bumps, or other hazards that could damage the Zoomie header set.

Baffle Installation

Zoomie and Chopster Header Baffle Inserts:

Due to possible liability issues, Sanderson does NOT provide mounting holes for mounting the muffler baffle inserts. The customer or installer is responsible for the safe installation and proper securing of the insert.

Baffle Installation Procedure:

1. First, make sure the inserts are the correct size for the application. Sanderson’s 1.875″ (1-7/8″) inserts are for small block engine applications, and the 2.250″ (2-1/4″) inserts are for big block engine applications.
2. For NEW installations – Notice that one end of each Sanderson muffler insert is partly closed off with a welded washer.
3. Use a tape measure to determine the depth of the insert from the end of the tube. Use that measurement to mark the inside of the header tube. The insert depth should be held up slightly from the short-side radius at the lower bend and not bottom out (see image below). Measure the insert depth for every tube.
4. Insert the muffler into one of the header pipes with the partially closed-off end first. DO NOT FORCE. The insert should be snug but not too tight.
5. There are various methods to secure the insert. Either drill a hole slightly in front of the insert and install a stove bolt and locknut (or use red Loctite), or drill and tap directly into the baffle ring, using an appropriately sized bolt with a small amount of red Loctite on the bolt threads
   1. NOTE: Some customers have used sheet metal or self-drilling/tapping screws to hold the mufflers in place, but such screws tend to vibrate loose.
6. When the mufflers are securely fitted in all eight pipes, the headers are ready to install on the engine.

Vortec-Based and BluePrint Style Heads

This informative article was written by Sam of Century Performance Center

NOTE: This issue concerns STRAIGHT PLUG Vortec-style small block Chevy cylinder heads, including the BluePrint heads

Vortec-style (including some non-GM aftermarket) cylinder heads use a different spark plug location than standard non-Vortec cylinder heads. Vortec-based heads move the spark plugs further from the chamber’s center and closer to the exhaust valve. This can cause a header clearance issue because it changes the spacing between the two center spark plugs, bringing them 1/2″ closer together. Some tubes require dimpling for spark plug clearance on exhaust headers with tight bends near the cylinder head (for example, the Sanderson CC158 header shown below). Dimpling of other tubes is sometimes required on other header designs affected by the spark plug location and up-down angle.

BluePrint cylinder heads are based on the Vortec spark plug locations. However, the BluePrint heads are manufactured with a raised exhaust port exit. This changes the up-down angle of the spark plug and the center-to-center distance of the two center spark plugs. Dimpling locations vary slightly between common Vortec-based and BluePrint header applications.

If unsure, please measure the center-to-center distance between the center pair of spark plugs on your heads. The standard distance is 4.5″ (11.43 cm) versus 4.0″ (10.16 cm) on the Vortec heads (See the image below). Additionally, one of the reasons we ask for the cylinder head brand, type, and part number is that every Vortec-style cylinder head does not utilize the exact spark plug location and angle. Having accurate information allows us to ensure that the proper dimpling is applied to the Sanderson header set for spark plug boot clearance during the manufacturing process.

Tube dimpling example, Sanderson CC158 for Vortec:

Additionally, the vertical spark plug location of some Vortec-based aftermarket cylinder heads may vary from the above examples. We may require the distance between the center of one of the mounting holes and the center of the spark plug hole (see image below). This ensures that dimpling is applied to the correct location(s) on the header.

What is a D-Port?

Sam of Century Performance Center, Inc provided this article.

We often see confusion in what is considered a D-Port cylinder head for small block Chevrolet engine applications. The problem originates in the technical understanding of what constitutes a true D-PORT versus a D-shape. The D-Port roof extends well above the centerline of the exhaust port, whereas the D-shaped port fits nicely inside what is deemed a standard port dimension. The graphic below shows that the d-shape easily fits within the typical round or square port flange opening.

Where other header manufacturers use a typical flat header flange and gasket for sealing, the patented raised flange design of the Sanderson Headers requires different flanges for different small block Chevy exhaust port shapes. Other header flanges often block the top of the exhaust port on D-port heads. When using a Sanderson D-Port flange, the port is not blocked. However, using the wrong flange with a Sanderson header may expose open areas that will not seal, creating an exhaust leak.

Examples:

1. Using a D-port flange on a typical GM head (standard round, square, or D-shaped port), the header port flange open is larger (taller opening) than the sealing area around the exhaust port (additional details below, comparing two BRODIX Track 1® cylinder heads)
   
2. Using a standard Sanderson header flange on a D-port cylinder head has a similar problem, where the cylinder head exhaust port opening may extend above the raised flange sealing area, again creating the possibility of an exhaust leak.

Here is an example of a small block Chevrolet D-port cylinder head that requires the Sanderson D-Port header flange.