An orifice with a 1 in. diameter hole is installed in a 2 in. sch 40 pipeline carrying SAE 10 lube oil at $100^{\circ} \mathrm{F}$. The pipe section where the orifice is installed is vertical, with the flow being upward. Pipe taps that are 10.5 pipe diameters apart are used, which are connected to a manometer containing mercury to measure the pressure drop. If the manometer reading is 3 in., what is the flow rate of the oil in gpm?