Engine shakes under acceleration

360LA the engine seems to shake under acceleration. It’s a hard vibration almost. As soon as it hits about 2,000 rpm and about 1/3 throttle it starts. Do you guys have any tips?
Could be imbalance or detonation, could be a miss... could be bad valve springs or could just be the tune of the carburetor but, I'm guessing you'd be hearing it too