virbration that is felt in seat, floor and dash!? Have replaced fan clutch, front wheel bearings, u-joints, swing bearings, 2 tires. still vibrates..whats up!?

Which two tires? When you feel the vibration (shake?) in the seat normally it has to do with the rear end, and in the tires.

replaced back tires could torque converter be involved?

Yes, what happens is the flex plate will crack. Take the inspection cover off and look at the flex plate for cracks, and check torque converter bolts.

replaced u joints.

thanks Rowefast--will check that out. still interested in other thoughts on it.

Check transmission mounts making sure they are tight.

No harm in checking what you can, but I'll bet it is in the flex plate. Thats about the only thing that could shake the dash. You should be able to feel the vibration sitting in park, motor running, not moving. If this is not the case then it is going to be something else.