S&S Super Stock cylinder heads for Twin Cam style engines offer significantly improved flow over stock cylinder heads and can be used with stock H-D 88" and 95" pistons as well as with S&S Twin Cam style pistons Because the stock Twin Cam Style head bolt pattern is large enough to accommodate a cylinder bore size of up to 4", all S&S heads for Twin Cam engines use the stock bolt pattern This means that S&S heads purchased for an 88" or 95" engine can still be used if a rider later upgrades to S&S 4" bore cylinders