51 Pump Two Stage Unit – Extended Studs Bottom Bi-Rotational With OB Bearing Sae 4 Bolt B 7/8 – 13 Splines First Stage 2-1/2” Gear #20 Orb Inlet And #20 Orb Outlet Gear Housing Second Stage Blank Bc 1 Gear Blank Gear Housing #12 Orb Inlet #12Orb Outlet Pec Rear Ports