Upper Rear Control Arms - Length?

Anybody know the center-to-center length of the stock upper control arms on a 69 Chevelle rear suspension? I have double adjustable UMI rear uppers on my car. I was pulling a late-nighter trying to swap out a torque converter in time to make it to the race track, and I noticed that the lock nuts were loose on one of the upper arms. In my late night stupor, I turned the adjusting sleeve many times instead of the lock nut, and got my rear end alignment all out of whack. Didn't have time to pull them, measure, and re-install, so tried to eyeball it. Took the car to the track, and the rear end being out of alignment gave me a wicked shimmy. Under hard acceleration the car pulls to the right, and when you try to steer it back straight, it goes into a shimmy.

Best thing to do I guess is to remove them, set them both back to stock length, install, and tune the pinion angle from there. If anybody knows the bolt hole to bolt hole length of a stock upper arm, that would be awesome.