OK. I need a rear sway bar, and am about to buy one, but will it mount up to my stock control arms? I have been told I need new ones that are boxed style... is this true? what do I all need to upgrade my stock suspension with a rear sway bar?

The thing is you should really get boxed lower rear control arms, because, the non-boxed arms are just pressed into a " U " Channel.

So when you tighten the sway bar bolts you can crush the arm. Make sense to you ?

You could probably use spacers, like a bunch of washers or short lengths of pipe. But you want to do this right. Right ?

You can get used factory boxed arms for pretty cheap anyway. (Thats what I did.) Just make sure you get the right ones. (I think 67 and before are slightly different than 68 and later.)

Saves you having to drill the holes for the bolts too. (Which I imagine is a pain.)

And you might as well get new bushings pressed in too.

Tell you though, this will be well worth the effort.
You car will no longer wallow around turns like a whale on a skateboard with loose trucks. You will be able to confound little kids in hondas that can't understand how two tons of fun kept up with their nimble little rollerskates on that twisty road. Well it will help anyway. :rolleyes:

Edit: Since you car is an SS it should have come with a rear swaybar, and even if its M.I.A., you might already have the boxed arms. Crawl under and take a look. ;)

There should be a plate visible running almost the full length of the arm welded on the bottom of the arm with two reliefs where the bolt slide thru.