How about the driveshaft place you had it shortened at. How good are they is it true. Anyone else near you to give there 2 cents in person. Maybe a new U Joint had a dry spot or been sitting and was dry in a spot but check how true everything is and see what seem to be wrong. I would not want to take it for a long drive and have it come home on the hook. You will aways be thinking about it when you go for a drive. If you are going to run the car at the track good enough is never good enough unless you have trailered it to the drag strip, even then it suck coming apart and having to fix something that should of been looked at.