6-71

Delco-Remy was a division of General Motors. The GMC Roots type of Blower, which this is was rated at number of cylinders and cubic inches per cylinder. 6 cylinder @ 71 cubic inches= 6-71The type were designed for Detroit Diesel Truck engines. I hope you are not really going to try to rebuild this to be functional yourself ? More to it than just assembling parts . Roots is the last name of the brothers who invented the pump. These were originally designed for blast furnaces and to exhaust the gases underground in mine shafts. Here is one source of rebuilder:
Roots or Twisted Roots Supercharger Remanufacture / Rebuild Roots or Twisted Roots Supercharger Remanufacture / Rebuild [Roots Rebuild services] - $772.00 : Jon Bond Performance, The Worlds Premier Supercharger Rebuilder and Parts Store