powerband":14k7n7uc said:
..... The 250 starts cold with the oil pressure guage pinned and cruises warm @ 70-80 psi. when driven hard and hot it still idles with @60-65 psi....
Yikes!
That's some bodacious oil pressure there pardner. WAY more than is healthy for your distributor drive, etc.
Oil pressure is sorta like blood pressure; you die if you don't have enough but too much isn't so very good either.
Oil pressure is nothing more and nothing less than a RESULT of resistance to flow. Several factors work together to make this happen, one is how big of a hole you are trying to force it through, another is how much VOLUME you are forcing through the hole, and then there is the viscosity of the liquid.
Let us examine a system with no pressure-relief valve.
The oil pump sees the engine as a big leak, and it is constantly trying to fill that leak. By pushing enough VOLUME of oil, it is able to fill up the leaks and even maintain some back-pressure (this is what your gauge indicates).
If we change any one of these factors, the oil pressure will also change. Make the leak bigger (worn out engine) and the pressure will drop. Pump more volume and pressure will rise (this is why it goes up at higher speeds, the leak is still the same but more volume is trying to go through the same hole).
Lower viscosity oil leaks out faster, so pressure will drop from this factor as well.
So, high volumes of high viscosity oil being forced through a small leak results in high resistance to flow (oil pressure).
Enter the relief valve.
The relief valve is really for safety; we don't want to break the distributor drive, nor do we wish to blow the oil filter apart. Given enough resistance to flow and a strong enough drive, most automotive type oil pumps could make several THOUSAND psi pressure. Yup, don't reckon that would be very good for our engines either.
Trouble is, when the relief valve opens, part of the flow is diverted AWAY FROM THE ENGINE, which is where we want it to go. If we want that oil flow going to the bearings (we do) then ideally we want to run the oil pressure somewhere BELOW the relief valve setting. Remember, a relief valve CANNOT raise the pressure, it only DUMPS excess pressure.
One really big, common mistake is to put too big of an oil pump in, then maintain the pressure via the relief valve. All this does is take extra power to drive, heats up the oil further, and diverts the flow from where we really want it in the first place.
I would try some thinner oil, dunno what viscosity you are using but 0w-20 might bring that pressure down to a reasonable level and your oil (and bearings) would run cooler as a result.
Joe
I echo the thoughts on cold weather starting. 
