I did find a 55.2 Chevy truck shop manual on line. So far I have found a reference in it that says the pressure relief valve on the pump would limit the oil pressure to approximately 35 psi and in "specifications" at the end of the chapter defines Oil Pump Pressure as 45 psi with no reference to rpm for both 235 and 261 engines.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
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