These core holders are routinely used for gas and liquid permeability and other core flooding experiments. With this design, the core holder does not need to be completely disassembled in order to interchange core test samples. After the confining pressure has been released, the end lugs and distribution plugs are removed and the core sample is easily removed from the sleeve. The sleeve and end caps remain in place within the core holder. Spacers are provided to accommodate undersized cores. The distribution plugs are provided with a single inlet and outlet. However, additional ports can be added as required. The volume of all ports and flow lines are kept to a minimum so that accurate flow data can be determined.