Hoping someone knows olds engines or enough that they can help me out. I have what look like vacuum lines coming out of the valve covers and the intake manifold on my 307. The driver side goes from the valve cover to the carb. The left side is open and goes nowhere. I'm wondering if these should be capped or should be leading somewhere? Or can I keep them like this? And what would, if anything, change performance wise if they are capped or not capped?

 

*im not an expert
I had a 307, same thing.
I'd say to put a filter on the drivers side valve cover, I believe all it is is crankcase ventilation, so all is well if one side is lined to the carb.
Shouldn't have a performance difference either way.
Again, I'm not an expert, so if someone has something better, I could use extra info if there's more to be had

 

One side is a PCV and the other should run to the air cleaner filter housing.