70/71 Challenger rear sway-bar was this an option? Rare or common if they were available?

I believe it was installed on the AAR. I would say rare. Firm Feel reproduces a factory style rear bar.

Also installed on the T/A Challenger and later as an options for other Challengers. So not a common option on the 70/71's

Thanks for the replies guys, i asked because i recently ran across one and i had never seen one before.
The brackets are bolted to the frame and not welded so i'm trying to figure out if it's original or an aftermarket, it looks like it has been on the car for at least 20 years if not alot longer.

Sway bar brackets bolt to the frame, four bolts per side the bracket forms a "C" around the frame rail... They aren't as rare as this thread makes them seem... After a certain production date all cars with rally suspension (all 340's & all R/T's) were supposed to get the rear bar.. There should also be a plate sandwiched between the axle & the spring that the links attach to...

mounting plates are getting more difficult to find. actual sway bar is easy to find.

I don't know how rare they actually are, but my 70 340 Challenger (A66)came with one.