Try to sort out Engine number on my 340 if its a 340s or not ? A guy have a lockt at it and told me it was . hers a bit info on the Engine cast number 2780930 3 it on every one from 68 to 73 built info 6-17-71 in front drivers side HM 340R 36680218
down at the oilgasket(0ilpann) B 145299 .And infront of the gearbox just about in the middel of the Engine its a big letter O I have read somevere that letter O or J means that its a S Engine (340s) if any one can help me its verynice