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 2)

This change affects S&S ® heads for Harley-Davidson ® Twin Cam 88 ® , and SSW+ heads only. This bulletin does not apply to S&S
cylinder heads for Evolution ® models.
As of late 2002, these S&S cylinder heads are no longer manufactured with the OEM style head breathing groove machined into the
rocker box gasket surface. These S&S cylinder heads are now manufactured with a shorter groove in place of the OEM style groove.
This change affects both the front and rear cylinder heads. See Pictures 1 & 2.
The revised groove as shown in picture 1 is still used for engine breathing, but is no longer compatible with Harley-Davidson ® rocker
boxes or aftermarket rocker boxes that use stock style breathing passages. Cylinder heads with the short breathing groove must use
S&S rocker boxes. The breathing groove change does not affect rocker box gasket selection. Both cylinder heads with either style
of breathing groove still use OEM style rocker box gaskets.
Twin Cam 88 ® style and SSW+ engines must breathe through the connection between the cylinder head and rocker box. The engine
breathing function is vital to engine operation, and cannot be by-passed.
Because of the time required to phase this change into production, cylinder heads with both early and late style head
breathing grooves are being sold during the changeover period. Heads are sold in matched pairs with either the short or long
groove, and should be installed as a matched pair. Rocker boxes for each type of head must be selected per the information
on the following page.
Picture 1 - S&S ® Cylinder Head
S&S Style Breathing Groove
Picture 2 - OEM Style Cylinder Head
OEM Style Breathing Groove
2