Crest CNC EJ20 Billet Case HalvesThe CNC Billet Aluminum EJ case seeks to change the Subaru performance tuning market by reinventing the EJ and addressing virtually every weakness that exists in max power builds. The Crest CNC EJ Block, (Formerly Willall) is machined from 6061 T6 Aerospace Aluminum and features Darton Ductile Iron Sleeves. The block is designed with increased material thickness over the OEM cast aluminum case halves and adds a unique 4 bolt bottom end for additional