Ok, sure then. You’re absolutely positive that two rear axles you have zero history on are both completely unaltered, factory original B body rear axles despite the fact that neither was original to the car they came to you in. I sure wouldn’t assume that at this point, but if you’re positive that’s great.
So why don’t you just measure the pinion angle in the Polara? You’ve moved perches so you’ve set pinion angles before, check the pinion angle and see if it’s within spec. If it is, your vibration is elsewhere. Simple.
