[G.M.]

46 the 50 lb pump you have will put out a lot more than 50 lbs. The output pressure is controled by the bypass valve in the pump, the valley valve, an oil leak, bad bearings or cam bushings. The valve not used to set the pressure must be set wiith a higher spring pressure so it don't efffect the the valve being adjusted. Any place oil can gush through freely will reduce oil pressure. When we rebuilt Skips 37 engine he grabed an old early style long pump and stuck it in oil and turned it by hand, a full flow of oil shot out in two turns of the pump drive gear. Skip said that looks like a good one. I said let's test it anyway. We ran it on the tester and as soon as we restricted the output the pressure dropped to zero. We tested another old long pump and it went up to 90 lbs with a tighter restriction. The 90 lbs in this engines pump is controled by the valley valve which we adjusted to 45 lbs with the plugs out, a mechical pressure gauge spinning the engine with 12 volts with a little oil in the cylinders. It runs with the same pressure we saw when spinning on 12 volts. G.M.