I think that the bars ended up being about 60" on the Camaro. The kit started out as the Pro kit #018904 from A.R.T. (
www.appliedracing.com) with the 84" bars. It is a complete weld together kit as the feet where the wheels bolt-in comes in 4 pieces for each side.
Zip,
The top bars have left and right hand rod ends on them so that you can spin them to lengthen and shorten them. The slip joint allows for the fine adjustments and keeps the top bars from trying to separate when loaded. The slip joint is held in position on the top tubes by additional sleeves that are on either side of the slip joint and are welded to the tubes.
Bill