[BCompy]

Bob, we have two different manufactures cars with two different drive lines .I think the Superformance driveshaft is too short to balance. I belive the machine shop told me anything under ten inches is not necessary.
All the pro's kept telling me that it could not be the driveshaft because I was feeling it in the front end. I only tried it because it was making me crazy and there was nothing left to change. I am only guessing the frames are so stout that vibrations can be transmitted in an unconventional ways. All the material I had read on diagnosing vibrations were written about unibody late model cars.
Who cares what works as long as it works!