all of them are the same fit, so it doesn't really* matter if they're .850 or 1.03 diameter the lengths are all the same for a-body
(some of the larger aftermarket bars were manufactured with the clocking off, but this was some time ago. it's been fixed for quite awhile and i haven't heard of any problems out there and i've not experienced any on installs. but something to be aware of if buying used)