Melling M55 done after 5000rpm?
I've read lot of things on the forum about the causes of oil pressure drop, oil level, windage tray, oil pick up height and its related brazing to the pumo body can afflict pressure.
Mine is very good, about 70 when cold and over 35 at idle at operating temperature, the problem pop out when engine turns close to 5000 rpm, the gauge pointer has a superfast vibration from around 5 to 35 PSI.
Looking for the cause on the web i've seen that some oil pump has problem over 5000rpm or so, any experience with them?
i'll tear down oil pan to check pick up height first (honestly i want to see bearings too) then braze the pick up or make a bracket for it.