Engine shakes BADLY!!

Yah. I'm at a loss just as much as you guy are trying to help me. I have rubber mounts with the Schumaker or whatever torqe strap. The flexplate is neutral balance for internal balance. The converter is fairly new 3500 stall.
I haven't looked to much into the tranny yet.
I guess I could do a leak down next.

Oddly enough my Purolator guy just went through this on his 350 Chev in his Camarrow. He chased it for months and months changing balancers, carbs, timing chain etc....

It turned out to be his Torque Converter. Food for thought. J.Rob