S&S Cycle Head Breathing Groove Change for S&S Super Sidewinder Plus (SSW+) and Heads for Harley-Davidson Twin Cam 88 Models - Manual (Page 3)

● All S&S ® cylinder heads with the head breathing groove placed in the new style as in Picture 1 must use S&S rocker boxes to
maintain the engine breathing function.
NOTE: S&S rocker covers provide superior breathing with maximum air/oil separation inside the rocker cover. S&S rocker covers are
designed fit both stock Harley-Davidson
® cylinder heads as well as S&S T-Series cylinder heads.
If Harley-Davidson ® rocker covers, or any aftermarket rocker covers that use the OEM style breathing arrangement are installed on
S&S heads with the groove machined as in Picture 1, excessive oil consumption and damage to engine oil seals will result.
● All S&S cylinder heads with the head breathing groove placed OEM style as in Picture 2 may use S&S, OEM, or aftermarket
OEM style rocker boxes.
Compression Release Notes:
The cylinder head breathing groove change also affects rocker box selection when using optional S&S Compression Releases, both
electric and manual. Listed below are the two types of cylinder head machining and the rocker boxes that can be used with each.
Cylinder heads with S&S style breathing groove: See Picture 1.
Electric Compression Releases: Must use S&S rocker covers only. In addition to requiring a center hole for clearance, this style of
head must use S&S rocker covers for engine breathing.
Manual Compression Releases: Must use S&S rocker covers only. Even though a center hole is not required for clearance, this
style of head must use S&S rocker covers for engine breathing.
Cylinder heads with the OEM style breathing groove: See Picture 2.
Electric Compression Releases: May be used with any S&S or aftermarket rocker covers as long as they have a center hole or
“chimney” for clearance of the compression release body.
Manual Compression Releases: May be used with Harley-Davidson ® , S&S, or aftermarket rocker covers. Manual releases do not
protrude past the rocker box base, and do not require a center hole for clearance.
NOTE: S&S does not approve of welding, cutting, grinding, machining, or any other modification to the head breathing design of S&S
heads. Any failures determined by S&S to have occurred due to head breathing modifications will not be covered under warranty.
3
CAUTION
Picture 1 - S&S ® Cylinder Head
S&S Style Breathing Groove
Picture 2 - OEM Style Cylinder Head
OEM Style Breathing Groove