Er, I think we need another description of the '67 factory traction bars vs. the aftermarket version that is most often associated with the word "Lakewood" (the yellow ones). I'll take a stab at it:
The '67 factory bars look like solid "I" beams and run from metal ears welded to the underside of the axle to a plate mounted to the bottom of the floor pan just inside of the rear frame rails. Thus the OEM bars run INSIDE of the springs (almost 1/2 way to the differential) and prevent fore and aft axle movement or axle twist
The Lakewood style bars are boxed metal that connect to the axle DIRECTLY BELOW the leaf spring and have a rubber snubber at the front. Thus they are not mechanically attached at the front end and they prevent leaf spring wind up as the front snubber restricts spring movement.
High performance '67 Camaros got 2 styles of single bars (both totally different from the Firebirds) mounted on the passenger side only.
Did I do good?
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI