The CS12 is a small block Chevy conversion header for V8 engine swaps in two-wheel drive (2WD) Chevrolet S-10 truck and Blazer (including GMC S-15) applications. The CS12 features a 1-5/8″ primary tube diameter and offers a compact header design that fits cleanly between the engine and frame rails. This is NOT a fenderwell exit header!
The CS12 header works with virtually all engine swap kits.
WARNING: The vehicle’s steering shaft will run between the engine block and header on this application. The use of solid motor mounts, engine plates, or the installation of a torque limiter is strongly recommended to prevent the engine from shifting which may cause the steering shaft to bind.
- Straight plug cylinder heads ONLY
- Shorter, header spark plugs are recommended
- Available in different tube diameters. For 1-1/2″ order #CS11; and for 1-3/4″ order #CS13
- For standard port angle plug cylinder heads, order #CS11AP or CS11AP-134
- For angle plug, d-port cylinder heads, order #CS11DP or CS11DP-134
Includes all hardware necessary for installation.
Engine: Small Block Chevy 265-400
Primary Tube Diameter: 1-5/8″
Collector Diameter: 2-1/2″
- 16-Gauge Primary and Collector Tube Thickness
- 3/8″ Thick Flange
- Patented Flange Design Requires NO Gaskets
- Tightest Fitting Header Available Anywhere!
- Made in the USA
- Header Bolt Set
- Collector Reducer Set
Our Ceramic Coating is recommended for every vehicle application and is the default finish selection choice above. To meet high standards of quality, We apply a multi-layer inside and outside aluminized ceramic coating in-house and then polish the coating to a high luster. This aerospace and military-grade technology adds excellent protection to your headers while offering the benefit of thermal control in your engine bay. It also improves cylinder scavenging of exhaust gases and increases the longevity of your header investment.
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 (and this includes some non-GM aftermarket) cylinder heads use a different spark plug location than common non-Vortec cylinder heads. Vortec-based heads move the spark plugs further from the center of the chamber and closer to the exhaust valve. This can cause a header clearance issue because it changes the spacing between the two center spark plugs, moving them 1/2″ closer together. On exhaust headers that have tight bends near the cylinder head (for example, the Sanderson CC158 header shown below), the dimpling of some tubes is required for spark plug clearance. 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 in addition to 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 the part number is that every Vortec-style cylinder head does not utilize the same 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:
What is a D-Port?
This article was provided by Sam of Century Performance Center, Inc.
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. As shown in the graphic below, the d-shape easily fits within the common 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 will 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.
- Using a D-port flange on a common 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)
- 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.