I have a new to me 1969 RS Z/28 that was recently restore from top to bottom. The issue I have after going through the car is a nasty driveline vibration. It seems to be coming from the transmission. I pulled the driveline and all the u joints are new a look good. I do have more that i think normal play in the output shaft. I am just not sure how much is excessive. When I push the shaft up and down I can feel play in it enough th hear the tranny " clunk" a bit. just searching a bit before I pull it. Also have an issue with the vacuum secondaries not opening up.