Just installed new rear end and suspension with new tires and wheels.I noticed that one wheel is 1/4" closer to the frame than the other side.Should the spacing be equal or is this tolerable on a '69 frame.I measured diagonally between all the body mount holes and they are all eqaul or with in 1/16". So the frame is straight.The only discrepancy is with measurements on one of the spring saddles/upper shock mount ,it looks like it was replaced,the rivets are now bolts and the welds are definitely not factory(way worse)

I don't know about Chevelles but my 68 Camaro vert is a little MORE than 1/4 to the pass side. Maybe 5/8". I did alot of resarch on that and from what I gather it is common. My whole suspention and body bushings are new. I ended up putting in a 3/16th spacer on one side because of my 275 tire. I now have 1/2" to the inner fender well on both sides.

It's common with pretty much every vehicle on the road. Some are worse than others.