These are replacement single plug cylinder heads of S&S® 3-7/16" and 3-1/2" bore P-Series engines, and for 1966-'84 HD® shovelhead engines that have been upgraded with the S&S® Retro Conversion Kit. Cylinder head kit includes front and rear cylinder heads, complete with valves and springs, cylinder head gaskets, pan cover gaskets, and exhaust port gaskets.
Note: These are not service part cylinder heads for panhead engines. They will not fit on stock panhead cylinders.Compression depends on piston type and engine displacement.
