EGR, I think. They can be removed and plugged, I believe. I have removed the air tubes in the 5A heads, my 81 Delta 88 had no tubes and factory plugs. The A4 intake is very rare up here, actually bought one from down there for the Olds powered 4x4. Almost all the 307's up here had the iron #17 intake and were non CCC QJet till 86 and with a few exceptions, the 88 CSC being one, only in C and D bodies.