Hello members.. I have a quick question.. after much perusing regarding 750k pistons.. I need to know if any year sohc K piston will work in the 1978 cb750 k... reason I ask, is that 77-78 pistons are very hard to come by and my options economically point me to the earlier reproduction offerings( pre 1977) ...is the only penalty is a slight comp. ratio difference? ( background , engine is currently going back to original bore 61mm from previous owners disastrous attempt at an 836 big bore - head/ engine and new OEM bore cylinder is/are circa. 1978k) much thanks!