I can't figure out what the second nipple is for that comes off my oil bath air filter. I know one goes to the oil filler cap. My PCV will go to the intake manifold that they had a rubber cap on. I still need to find PCV, grommet and hose to fit. My one barrel carb does not look like any that are in the repair manifold. I also noticed that there is one hole with threads open on the carb which may lead to the other nipple on the air cleaner or maybe to a spark control valve I don't know and can't find anyone around here in az that knows anything about this nor any diagrams online.