The 1954 235/261 trucks engines had what Chevrolet called a full-pressure lubrication system. However, the normal oil pressure was also a higher pressure in comparison to the older-style lower pressure 235/216 engines.
low-pressure gauge high-pressure gauge Nonetheless, when rotating the oil pump with most drills, the oil would mostly drip from rocker arms. However, we recently observed a little fountain-like-upward flow from the holes on top of several rocker arms on two 1959/60 261 engines, and they showed 5-10 psi readings on the oil pressure gauges.
