Big Bore Headset (Shovelhead), Dual Independent Intake system

US$2,395

Speed And Science Big Bore (3-5/8″) CNC Billet Aluminum Headset for the Harley-Davidson™ Shovelhead models, with Dual (independent) CNC Billet Aluminum Intake Manifolds

 

Available on backorder

Description

  • Speed And Science ® designed Big Bore (3-5/8″) Billet Aluminum (6061-T6) Heads/Intake system for the Harley-Davidson™ Shovelhead models.
  • Bolt-on installation for all ’66-’84 models equipped with 3-5/8″ Bore cylinders. Designed to match S&S™ Sidewinder series pistons (P/N 106-5535,  not supplied).
  • This system achieves very strong torque curve and very respectable HP that peaks exactly where needed. This makes a superb street engine that will keep going strong for a long time, not just a 1/4 Mile!! We went to great lengths to make sure that our product is user-friendly and easy to service down the road also. No custom pistons, valves, guides, fasteners, etc. to worry about. Nobody offers that – there’s no hidden cost with our product!!!
  • Fast, very efficient ports designed to make peak power/torque within the useful RPM range. This is where a lot of people get confused. Please remember, the right balance between flow and velocity makes a good port. We could’ve made ANY shape ports and get HUGE flow numbers, but have made it RIGHT instead. As a result, your bike will pull hard from the get-go all the way up to the redline. The longevity and fuel mileage won’t suffer either.
  • Proprietary, super-fast design of the combustion chamber yields 10.05:1 w. 4-1/4″ stroke (10.55:1 w. 4-1/2″ and 10.80:1 w. 4-5/8″ stroke) calculated compression ratio with Sidewinder pistons. Works well on the hi-octane (e.g. North American 94) pump gas. Compression releases included for easy starting.
  • AV&V components accept up to .640” valve lift (with optional hi-lift springs), with almost .200” lift before valve-to-valve contact. Using tall camshafts may require an additional machining to provide necessary clearances.
  • Increased cooling area drops the head’s operating temperature up to 35F.
  • Dual (independent) CNC Billet Aluminum Intake Manifolds (seals included). Carb interface: 41.4MM ID, 2-3/4″ x 5/16″ bolthole spacing. We have completely redesigned the Intake <–> Head interface, thus eliminating vacuum leaks.
  • Exhaust interface accepts both OEM single-bolt flanges as well as STD’s three-bolt pattern.
  • Hi-tensile steel thread inserts (headbolts, intake, exhaust) installed; all original thread sizes, no need for “special” fasteners.
  • OEM oil drain location.
  • ***The difference in surface finish between the Intake (coarser) and Exhaust (smoother) ports is intentional.
  • Warranty details and conditions are listed in the Installation Manuals ( Manuals download page )

Additional information

Weight 22 lbs
Dimensions 22 × 12 × 6 in

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