Q: Flat spot in motor.

A fixed hesitation point when accelerating points to a specific mechanical issue either in the ignition or fuel system. The mechanical advance in the distributor needs to be checked for free motion and base timing would need to be checked. In the fuel system the checks will change based on whether you have a carbureted or gasoline injection system. You may want to enlist the help of a mechanic, like one from YourMechanic, who has the tools and equipment to diagnose the cause of the hesitation.