 A total of 111 units were rebuilt to "GP8" for the Illinois Central and Illinois Central Gulf.Core units used in the construction of these units were Illinois Central GP7, GP9, a GP8, C&O GP9, D&RGW GP9, DT&I GP7, N&W GP7, P&LE GP7, QNS&L GP7, RDG GP7, St.J&LC GP9, SLSF GP7, and SP GP9.The Paducah Shops also rebuilt 16 Conrail GP7s to GP8s.