Violent Take-Off Shudder

Tend to agree with the clutch disc diagnosis. However I have to ask a couple of things. Was block align bored? Was bell housing alignment checked during the build-up? What first gear is in the tranny? Years ago I was talked into installing a metallic disc clutch behind my 440. It was very hard to take off smoothly from idle. The problem resolved itself when the clutch disc came apart while driving back from lunch one day. I didn't replace it with another one! Good luck!