I have a 1978 slc, only 89,000 miles on it. The car was purchased from a friend who had it parked in his garage since 1985. The passengers side valve train has some clack, and it has just recently started smoking out of the passangers side exaust pipe (no smoke out of the drivers side). I don't know much about these mototrs, but I suspect its valve guide related? Any pointers?