I have a new rear u-joint in a 74 B-body that may be the cause of a new vibration. The frequency of the vibration tells me it's comming from the drive shaft. I swapped in a known-to-be-good hogs head at the same time I replaced the u-joint. This was after the yoke broke.
A Mopar friend said to use only Dana-Spicer u-joints to avoid the occasional bad u-joint that other manufacturers seem to produce. The suspect u-joint is a Precision 347(made in USA). How common are out of the box defects?