Bill that is an excellent question. The third member was made by Performance Products. I am assuming the lash is correct, but it may be an issue to look at after I get all these other questions answered.
Now, as far as the drive shaft. I took it into Drivelines NW today where they made it. Here is the issue. When I put the 9" rear end in the car, my existing driveshaft was too long. So I took it to them for shortening. They showed me that my driveshaft was worn completely out. I agreed. They made a new one, 4" instead of 3 1/2 diameter and were supposed to make it 1 inch shorter. Instead, they made it one inch too long. Took it back and they agreed they screwed up. So, they said they shortened it one inch.
Took it home and installed it. Now here is where the funny stuff begins. When I talked to them today, they thought, as you, that the yoke might not be going into the rear far enough, therefore creating a vibration.
So, took the yoke home, measured the distance from the centerline of the yoke u-joint to pinion yoke c/l and called them with that dimension. They said my driveshaft was 1" too short and could be causing the problem. Now, did they cut off 2" the 2nd time? No way to know.
Anyway, they are going to make a new one. I will let you know what happens and thanks a bunch for all the great input from you all. Together, we can conquer the world, by ourselves we just screw everything up. Maybe a little too philosophical on the conquer the world thing. Larry