Page 285 of High Performance Parts for American V-Twins 2008 by S&S Cycle

1958-2008 50th ann iversary s&s® super stock® cylinder heads and kits for 1999-up big twin engines to get more horsepower out of an engine you have to get more air into it ports in s&s super stock cylinder heads offer significantly improved flow over stock on the same superflow® 600 flow bench our 89cc s&s super stock® heads flowed 264 cfm 25 of water compared 182 cfm 25 of water for stock heads from a harley-davidson® twin cam 88® engine in addition to improved flow the s&s heads allow the use of cams with as much as .640 of total lift tdc lifts depend on the type of pistons used see notes about valve to piston clearancing pictured right s&s cylinder heads shown here in the natural aluminum finish are also available in black powdercoat finish heads have the stock head bolt pattern and can be used for stock bore and s&s 4 bore engines two styles s&s super stock cylinder heads for 1999-up big twins are available in two versions one is the stock compatible version for use on stock displacement engines and the other is the performance version for large displacement engines up to 4 bore both are available in natural aluminum and black powdercoat finish performance heads for large displacement engines the performance version is designed to be used on large displacement high performance motors and has an 89cc combustion chamber since these heads are intended for big inch engines it is assumed that s&s electric compression releases will be used although a threaded plug is provided to seal the machined hole in the event that compression releases are not used these heads are not compatible with stock rocker boxes and must be used with s&s die-cast rocker boxes the performance heads feature 2.000 intake valves and 1.605 exhaust valves for improved flow the larger valves make these heads unsuitable for use with stock harley-davidson pistons due to piston clearance problems notes when 79cc heads are used with stock h-d® pistons tdc lifts of up to .186 for intake and .179 for exhaust can be used without additional valve pocket clearancing this allows the use of s&s 510 570 and 585 camshafts if cams with higher tdc lifts are used or if the heads are decked valve pocket machining will be required if 89cc heads are used with stock h-d pistons valve reliefs in the pistons must be machined both 89cc and 79cc heads may be decked as much as .060 to increase compression if heads are decked valve to piston clearance must be checked if stock h-d pistons are used valve pockets must be remachined moderate valve spring force in s&s super stock cylinder heads allows the use of camshafts designed for the stock style chain cam drive system however for maximum reliability and performance we recommend the s&s gear drive cams s&s cylinder heads with 79cc and 89cc chambers use different valve sizes so it is important to order the correct replacement valves valves have part numbers etched below the keeper grooves for easy identification stock compatible heads for stock displacement engines s&s stock compatible are an economical performance upgrade for 88 95 and 96 engines that do not require s&s electric compression releases what makes them economical is that they are compatible with stock harley-davidson® rocker boxes which saves the extra expense of purchasing special rocker boxes these heads are machined to allow the use of s&s compression releases if needed but come with threaded plugs that seal the machined holes when compression releases are not required if s&s electric compression releases are installed s&s rocker boxes will be required to provide clearance for the release body and solenoid the 79cc combustion chamber yields a higher yet manageable compression ratio ranging from 9:1 to 10.3:1 in these smaller engines see compression ratio chart to maintain higher velocity in smaller displacement engines these heads have 1.940 intake valves and 1.575 exhaust valves s&s stock compatible heads may be used with stock h-d pistons or s&s pop up pistons with most bolt in cams without valve clearance problems order toll free 866-244-2673 8-2

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