My poor diesel friend has an oil leak.  Here are some of the details.

The oil leaks from areas where there are seals, main seals, head gasket,
etc.  There does not seem to be leaks at the filler tube, oil pressure
sensor, or valve cover gasket.

I replaced the head bolts.  The leak was better then went back to the same
rate.

The rate of leakage increases with engine speed.  At an indicated 50mph (62
actual, don

�t you just love VDO) a small amount of leakage, and a few spots
on the rear window.  At an indicated 55mph the rear of the van gets covered
in oil spots.

Then I replaced the engine with a long block from GEX.  I have the same oil
pump, fuel system, valve cover, oil pan, exhaust system, hoses, vacuum
pump.  The oil leak still occurs, maybe at a lower rate but the rear of my
van is covered in oil.

Any suggestions would be greatly appreciated.  I have followed the advice
of Stuart Hutton and tracked down the leaks.  I am just wondering why I
have them in the same place with a rebuilt motor.