Camshaft internal metal Bush for advance rod. 2 Used per camshaft on 70-79 models (Points Ignitions) and also required if using Boyer ignitions. Fits inside cam in center (one each side) Note: These are usually missing from 1980-84's. The advance rod rotates inside this bushing unless a Pamco Electronic Advance is used in which case the rod is fixed in one position. Older Non Electronic advance Pamco ignitions require the advance rod to rotate.