driveline
Jayson,
My driveline shop suggested a doner driveline out of, I believe a 318i, it has a splined shaft portion that will come in handy to take up any small errors in measuring.
Also be sure to see if your center bearing carrier is the newer style, or the "ruth goldberg" contraption. Mine was the later, it's a complicated setup with springs. I decided that when I end up installing the 5 speed, I was going to weld in hangers on the tunnel for the later style. From what I can gather, this style was introduced sometime in '67, although I'm not certain. Hopefully yours has the later style.