According to my 1966 Ford Factory Manual, the "jiggle pin", which is installed in the front of the engine, center gallery, is there to let air out of the system. It goes on to say that
oil for the chain and sprockets is suposed to come from the front cam bearing/cam journal.
I never bothered with the jiggle pin. I just tapped and installed a threaded plug.
As I mentioend before, bearing clearances, particularly crank main bearing clearances, is what affects
oil pressure at lower rpms (where the pump bypass is not yet activated). My clearances are at 0.0025". I think the book says the normal clearance is from 0.0005 to 0.0015 inches. With these latter tighter clearances one can expect higher
oil pressure at hot idle.
A HV pump helps keep oil pressure up at those lower rpms, but once the rpms are high enough to open the pump bypass, the oil flow (into the engine galleries) from a stock or HV pump will be the same. The excess from the HV pump will come out the bypass and return to the pan.
10 psi per 1000 rpm. OK...say in a SBChevy you get 10 psi at the guage, but only 5 at the bearing. In a BBFord, with 10 psi at the guage, you may only get 3 psi at the bearing. Just throwing out numbers.