Is the accelerator pump shooting fuel the moment you move the throttle? It should be giving a shot instantly.
Do you have the original single diaphragm vacuum advance and points distributor? Is the vacuum advance retracting when vacuum is applied. Does it HOLD the vacuum? Be sure the vacuum advance is moving the advance plate in the distributor when vacuum is applied. They can stick same as the mechanical advance. Try switching the vacuum advance hose from whatever it's on now (ported or manifold).