S&S Cycle

ALUMINUM CYLINDER HEADS FOR 1937–’48 FLATHEAD SIDE-VALVE BIG TWIN ENGINES

FITMENT • 1936 V model engines • 1937–’48 U model engines FEATURES AND BENEFITS • Precision cast aluminum construction for better cooling • Nine head bolt pattern OPTIONS • Available compression ratios: 5.5:1, 6:1, 6.25:1, and 7:1 (80") • 14mm or 18mm spark plug hole KIT CONTENTS • Front and rear cylinder heads • Copper head gaskets • Head bolts NOT included ALUMINUM CYLINDER HEADS FOR UL AND ULH MODELS Description Part # Set 16671-36, 16661-40 106-2475* *Special Order: Download the Special Order Form at sscycle.com/soforms

CYLINDER HEADS FOR 1940–’47 OHV BIG TWIN ENGINES

FITMENT • KN-Series engines • 1940–'47 OHV big twins

• 1936–'39 with a manifold upgrade FEATURES AND BENEFITS • Made of engineering-grade grey iron—better heat dissipation, less sound transfer • Durable stock-look black powder coat finish • Counter bore for 61" cylinder fire ring • Set up for o-ring manifold or late style port plumber fittings • 1.940" intake and 1.750" exhaust valve

• Valve springs allow cams with up to .480" lift • Compatible with stock or S&S valve cover "tins" OPTIONS • Fully assembled or unassembled

• Fully assembled with valves, rocker arms, tins and housings complete • Guides installed for use with S&S® Vintage tins (valves ground) • Guides not installed for use with stock tins (valves not ground) • 14mm or 18mm spark plug hole

REPLACEMENT PARTS: SEE PAGE 190

CYLINDER HEADS Description

NOTE: Stock 1948–'65 head bolts can be used in stock bore applications and are available on page 149 , big bore applications must use the S&S 12 point head bolt also found on page 149 .

Part #

106-4929*

Fully assembled heads

148 S&S Vintage 1926–1999 Order 608-627-1497