78 930 turbo oil pressure

[fredmeister]

I have a question on what oil pressure should be expected to see on a rebuilt 78 930 turbo engine.
I drove a 78 turbo that I was considering buying with a freshly rebuilt 3.3 liter engine. The oil pressure on the gage read about 1 bar at idle but only peaked at barely 3.0 bar even under boost and 4500-5000rpm. This bothered me as I expected to see roughly 1 bar for every 1000rpm.
The seller says that he thinks the gage is off calibration because the oil temperature reads high and the pressure low when I pointed out my concern. He said that his experience was that all cars read differently, some high some low......my 911SC reads 3.5-4.0 bar at anything above 4500rpm.
The engine was freshly rebuilt less than 800 miles ago with new bearings and pistons/cylinders, cams, the works.
Is this possible or anyone have an opinion to give before I pursue buying this car?

[mb911]

10 psi for every 1000 rpm is the rule that most go by so with that I think this reads a little low. If I were interested in the engine/car I would verify with a standard oil pressure guage (manual fed) then there would be no suprises