Drivetrain vibration problem

Had the same problem with my Dart. The factory driveshaft which is .060 tube thickeness give or take a few thousandts couldn't handle the additional torque that my stroker put out and it wasn't long before the vibration got worse. At first it was very minor and I was chashing my tail to figure out wtf was going on. I had the driveshaft balanced in the very beginning of the build along with new u-joints so I never gave the driveshaft a thought. I had all the tires rebalanced and they were fine. Finally I went back to the driveshaft and had it rechecked. Sure enough it was way out of balance to the point it couldn't be balanced. I think one to many burnouts had a little something to do with it if you get my drift. Had a new shaft made with .087 tube stock and everything is smooth again. The factory shafts just weren't that strong, at least on some of the Abodys.