Course, I could have axle wrap...

Enter option C (which I dunno what the symptoms exactly are)

C: Possibly axle wrap on take off, the leaf springs are shot imho. The overload is flat, and the other leafs are nowhere near as round as they should be.

Any large bump will jar you. I havent found suitable bolton replacements other than add a leaf packs and progressive leaf packs, gonna call a spring shop and see if they can build me new packs possibly for a mild lift of 1" since it kinda sits low now.

It does make sense its axle wrap on take off, it feels like its wiggling along and at speed on the gas the vibe got better but is still there. If I take off easy you dont notice a thing, take off hard and bingo. Perhaps the softer springs are allowing the rear to tilt-thus my vibration? on take off of the wiggle and at speed, since less torque I dont feel it as much?

Another thing I noticed is if I brake stand the rearend wants to hop all over the danged place like crazy!