Pinion angle?

74 Challenger I swapped in a Gen 3 hemi and 8 speed now have a pretty bad drivetrain vibration. The engine/trans in angled down 2.5 front to back. The drive shaft is 1.9 down front to back. The pinion is .5 up . Any suggestions how much to shim and up or down . Or do u think its not the problem . It's a leaf spring car