Description
SHOVELHEAD PORTED HEADS DISCLAIMER: *** Due to the hi-power output and certain mechanical features, this headset is to be installed/tuned ONLY by an experienced engine builder. Bike to be ONLY used on a closed course. Limited Warranty applies. ***
- Shovelhead Ported Heads by Speed And Science ®. This is the MIT version of the Big Bore (3-5/8″) Billet Aluminum 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 headset has been designed to make POWER, but our product is user-friendly and easy to service down the road also. No custom pistons, valves, guides, fasteners, etc. to worry about.
- 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 (85CC chambers with Sidewinder pistons). Works well on the hi-octane (e.g. North American 94) pump gas. Compression releases included for easy starting.
- Valvetrain (AV&V and KPMI) components accept up to .625” valve lift, 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.
- Single (Y-Split) CNC Billet Aluminum Intake Manifold (seals included) interfaces with Super E, HSR 42MM, HSR 45MM, etc. We have completely redesigned the Intake <–> Head interface via proper EVO seals to eliminate 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 )























Excellent product, machining is exceptional, the extra cost to get the product to the USA is crazy, but that is not the fault of Speed and Science.
Heads looks great and perform even better. Fitment is spot on
Parts came in quick and look amazing!
Great