9 1/4 differential question

[ottawamerc]

Hi guys

I have been chasing down this vibration in my car for some time now and some of you have mentioned that the drive line angles could cause this issue. I didnt really suspect that to be an option due to keeping a mainly stock drive train, now saying that I know 71 Chargers didnt come with 9 1/4's but hey they fit. I checked the specs on them from my 8 1/4 original and I was sure they were the same except I needed the shorter drive shaft. Now today I took the time and crawled under my car and ya the rear u joint doesnt really look well lined up So does a 9 1/4 C body diff fit in other than its 1.5" overall wider at the tires, are the angles ok???

Just wondering and looking for input

Thanks

Scott