1st gear vibration

Posting for a buddy, 67 Barracuda 383 4 speed has a bad vibration taking off from a dead stop and only at low RPM shift into 2nd with higher RPM and it starts to go away 3rd and 4th no vibration. Had the tranny rebuilt and clutch, pressure plate and bearing are all new. Vibration is so bad it shakes the dash. Anyone had a similar issue?