Vortec Engine History and Cylinder Heads

Categories: Cylinder Head Tips
Vortec gets its name from a line of small block engines for GM trucks. The name first appeared in a 1984 advertisement for the 4.3 L V6 that used “vortex technology” to produce a swirl inside the combustion chamber that allowed for better air/fuel flow. Nowadays, this technology is used on a wide range of engines. Vortecs are highly prized among many van and truck enthusiasts, as they are among the best budget options for their time.

The Debut

From 1996 to 2000, GM truck and van 350 engines came equipped with L-31 Vortec cylinder heads. Built of cast iron, these powerhouse heads upped the horsepower of these engines by magnitudes. This is primarily attributed to the high port flow in the .300”-.500” valve lift area, wide bowl, and back-cut intake valve and exhaust. Some circles believe the Vortec L-31’s small exhaust port is easier to work than intake, making it an excellent choice for split-duration camshafts. The biggest design shift from prior iron GM heads is the combustion chamber, built in a ‘double-quench’ style. Such a unique cylinder head design has become popular among enthusiasts interested in their own budget, small block engine builds. L-31 Vortecs came in two castings, #906 and #062. Courtesy of a later-corrected magazine article, there’s a common misconception that #906 is the superior between the two. In reality, both castings are capable of producing roughly the same amount of horsepower and are interchangeable.

Making History

While the L-31 was an impressive debut for GM, they weren’t quite finished. Many heads built before the early 90s required high degrees of ignition timing lead. Their burns were uncontrolled and random, leading to a less efficient combustion. The Vortec was revolutionary in such a market. It required only 30-32 degrees of lead, reducing the amount of pressure the engine had to fight. This produced more power on less fuel. A guiding principle behind the development of Vortec is efficient flow at all levels, particularly low lift flow. Turbulence creates low-pressure pockets which make it difficult for a port to pass air. Laminar flow, meanwhile, keeps the air free of pockets, leading to a smoother flow. Overall, due to this high velocity laminar flow, controlled high swirl chamber, and flat top pistons, few aftermarket heads can compete with the Vortec.

Spark Plugs

  • 5613611 R44LTS, set of 8
  • 5614210 MR43LTS, set of 8
  • 25164641 #3, Rapid Fire style, set of 8
  • P526S Accel U-Groove “SHORTY” Double Platinum Header Plugs approximately 3/16″ shorter then R44LTS plugs, set of 8
  • RS12YC Champion
  • Autolite 104 or 26
  • ACCEL 516
  • Bosch HR10B or HR10BX, HR9DC

Types of Vortec Heads

  • GM L-31 Vortec
  • GMPP ‘small port’ Vortec Bowtie
  • GMPP ‘large port’ Vortec Bowtie
  • EQ “Lightning” Vortec Style
  • Dart IE Vortec
  • RHS Vortec
  • GMPP ‘Fast Burn’
  • Edelbrock E-Tec 170
  • Edelbrock E-Tec 200

The Cylinder Head Repair Experts

Clearwater Cylinder Head Inc. (CCH) is a reputable, experienced (over 25 years) dealer. We specialize in providing quality and warranty-backed rebuilt cylinder heads for a variety of vehicles (cars, trucks, boats, etc). With a massive online catalog of cylinder heads, we most likely have the cylinder heads you need for your car, truck, or boat.

The knowledgeable staff at CCH is happy to help you find the Vortec cylinder head that is right for your engine. Please contact Clearwater Cylinder Head Inc. toll-free at 1-800-572-1963 Clearwater Cylinder Head, Inc. thoroughly cleans, inspects, and pressure tests all our cylinder heads. All machine work performed on the latest state of the art equipment. Head is complete and ready for installation. Please see our warranty policy and customer reviews to get a sense of our product quality commitment and service level.