Wellhead flow block and flow control mechanisms

A kit of flow restriction plugs for use with a flow control insert for a wellhead flow block, comprising:

• a first flow restriction plug configured to provide a first amount of flow restriction;
• and
• a second flow restriction plug configured to provide a second amount of flow restriction that is different from the first amount of flow restriction;
• wherein the first and second flow restriction plugs both include:
• a cylindrical body having first and second ends and external threads on an outer surface of the cylindrical body;
• and
• a central cylindrical aperture in the cylindrical body that extends from the first end to the second end of the cylindrical body;
• wherein the central cylindrical aperture of the first flow restriction plug has a first diameter, wherein the central cylindrical aperture of the second flow restriction plug has a second diameter than is different from the first diameter, and wherein both of the first and second flow restriction plugs can be mounted in a cylindrical wall of a flow control insert by screwing the external threads on the flow restrictor plug into internal threads on the cylindrical wall of the flow control insert.