demon seed: yes this vibration is speed related...
1970pavalient: no play in the driveshaft
67dart273: this drive shaft was taken to a driveshaft shop...this is all they do...it was lengthened with a new tube rebalanced and new u joints installed, the extended length was determined by them and the measurement was taken with the axle tubes supported with jackstands, pinion angle was measured and was within specs as determiined by the driveshaft company
purplehase:new tires and wheels balance ok
oktire: this vibration is coming from the midpoint to tail end of the car
GUP:new tyranny mounts and new motor mounts but i will check bolts for tightness
moper:this vibration only happens aroun d 55 mph and is not rpm related i feel it in the seat and in the center console and it does get worse...starts at 50-55 gets a little worse arouind 60...it seems as though i can feather the gas pedal and get it to smooth out a little bit... i havnt tried slipping it into neutral at the vibration speed ...i will try that... when I shift down to second gear and at same rpm there is no vibration...also when in neutral sitting in driveway at same rpm... no vibration....
i hope this info helps...i'm at my wits end with this problem
