"The polyurethane bushings don't work with the earlier strut rods. "
I believe you, but I don't understand why these are sold as "A-BODY 66-76". Written right on the box.
That's easy, it's wrong. And it has been for a
long time. There's numerous threads on here about the poly strut rod bushings not being the correct size. It's a well known issue. Some manufacturer's versions are closer than others, but pretty much none of them are right. And keep in mind you're comparing old worn out bushings to brand new bushings, even the old ones were thicker than that when they were brand new.
Also, FYI, you have two different strut rods in your picture. 73-76 strut rods have course threads, the earlier ones have fine threads. The length of the threaded end is different too, on the 73-76 strut rods its ~3.4" from the end to the shoulder, on the earlier ones it's 3".
All of this is why I don't even bother with the stock strut rods on any of my cars. All of them get adjustable strut rods. The re-pop strut rod bushings aren't the same as the originals (even the rubber Moog versions), although the ones for the 73-76 strut rods are closer. But even then, the original strut rods were really just a "one size fits most" item. As long as they're sort of close to the right length the alignment can be made "close enough" for the factory tolerances on the factory alignment specs. But that doesn't mean that the strut rods are actually allowing the lower control arms to move freely and without any binding, it just means it was close enough for the factory.
And of course when you actually set the alignment specs to what they need to be for radial tires (which is totally different than the factory alignment specs!!!) the strut rod length can cause problems again with getting the right amount of caster. The adjustable strut rods can be set to YOUR car, so your suspension moves freely through its entire range. Sure, they're more expensive, but they work a heck of a lot better and are easy to set.
