I have read and have been told that you can make your own traction bars. How do you do this because I have a 66 chevelle that gets bad traction.

I think that I'd cut loose with a couple hundred max and buy the JEGS lift bars, used to be SSM liftbars, they work great for me.

or you could do this. if you dont have the money, but can weld and enjoy this sort of thing, look what i did here.
http://home.comcast.net/~petelohr/einstyn1/einstyn-07.htm
its the same thing as ssm bars but its not a bolt on mod. and you really only need to do the passenger's side of the rear. tried and tested!
http://home.comcast.net/~petelohr/einstyn1/rearbkt08cut.jpg

If you don't do both sides, do you wind up steering the axle under acceleration/braking because of unequal torque reaction?

no. as a matter of fact, the drivers side is naturally pushed down due to the torquing of the rear end. it ballances out.