Calc Bar Rate for Rear Sway Bar

[David Pozzi]

The trouble is, even with a rear bar rate, you don't know the motion ratio so the rear bar "effective" rate isn't known.
You do want the front bar rate to be higher than the rear.

I would take a guess that the front bar rate should be in the 800 to 1100 lb range. It could go as high as 1500 lbs if you have wide sticky tires an autocross but for a street car with not huge tires you won't need as much bar. That rear bar is delivering less than rated because it's attached to the lower links. Maybe 2/3rds or half of what the bar is rated at. The front bar is also delivering less than rated depending on where the end links attach to the lower A arms.

I'd look at what size bars are used on a Chevelle and size yours to be similar.