How do I remove lower control arm on a 67 barracuda

The guys nailed all of it above. While I'm still not an experienced mechanic, this is one job that I've done four times now. All I can say is that there's no magic here. Everything that needs to come apart is visible. Just have the right tools on hand, make sure the car is fully supported. I always set the parking brake, chock the rear wheels, use jackstands (as suggested above) AND leave the jack under the K-Member, supporting some of the weight.

So I don't have much to add to what has already been said but perhaps I can add some detail?

The parts likely to give you some trouble will be getting the torsion bar to back out of the mounts (in particular, the one on the body of the car), especially if it's never been apart. As mentioned above, make damn certain that the adjuster bolt (underneath the arm) is backed out to the point where you can wiggle the adjuster. If you don't do this, the torsion bar will be preloaded...and even a slight amount of preload may make it impossible to get the bar to budge and if it does, it's going to go "bang" and possibly damage the car or your person. Don't forget the retaining clip at the tail end of the bar. It will come right out with pliers. It could be hidden by grime so it's worth mentioning again. ;)

Second, getting the lower ball joint off of the arm can be a pain without a ball joint tool...but it can be done, if you're lucky. The picklefork (as rustycowl mentioned) will be your best friend here. You'll absolutely want to install a new balljoint at this point (you'll probably wreck the boot when extracting it anyway) and I'd consider saving yourself some hassle and getting a new assembly with the joint already installed in the forging... Unless you're adventurous and want to press the new one in yourself.

Keep us posted. I got a lot of help from this form so I'm more than happy to try to answer any questions if you get stuck.