[mrolds88]

Tim, I have a 96 Burb and can give you whatever measurements you need/want. Now as far as the headliner/a/c headaches, I may have an answer for that. They used to make (and I'm sure they still do) rubber inserts for this need. They have a brass insert in the small end. Drill your hole and drop in. They kinda look like a top hat from the side. Then mount whatever and tighten the screws down and it squeezes the rubber for a tight leak free mount. I'll do some looking for them.