273 rocker arm adjustment

The whole point of suggesting that a lighter oil be tried is for flow rate, not for pressure. The pressures inside the SBM rockers are already very, very low... like under 10 psi and probably only a couple of psi at idle. There are roughly half a dozen or more flow restrictions in the path from the oil pressure sensor before the oil gets into the rocker shafts, not counting the 'timed' oil restriction in the cam's 'flow interruptor'; that only lets oil flow for roughly 5% of the time. Since these rockers have been modified for MORE outflow, and there is another added minor restriction (head studs), anything that will increase oil flow ought to be considered....IMHO.