911 oil pressure and cooler

[Tspringer]

I just bought a '69 911S with a hotrod 2.6 engine (It came with the stock 2.0 S engine as well). The engine was built by Supertec in CA. It was installed 1 year ago and has about 2K miles since. This engine has Mahle P/C's at 9.8:1 compression, MFI rebuilt to RS specs, SSI's, lightweight flywheel and trick clutch. It also has RSR sprint cams, big valves and ports. The case was updated for an SC oil pump among other stuff. Supertec claims 230hp on the build sheet. The thing does run like a scalded dog.

My question is regarding the indicated oil pressure. I have owned a number of 911's, but it has been several years since my last one. This car, warm at idle, indicates very low oil pressure. Even when cold, at 3K rpm it only indicates 40-50lb or so. When hot at 5000rpm it indicates 55-60lb. Sometimes it seems to indicate more, other times less at any given RPM. Im not sure if the light indicating low oil pressure comes on or not at low rpm when warm. The upper light on the guage is on at times, the lower light I believe also comes on. Which one is the warning light for low pressure?

The engine does not make any bad sounds and runs great. Could this be a sending unit or guage issue? Where is the sending unit on the engine? Is it possible to connect a mechanical pressure guage to the engine to test actual pressure?

This car also does not currently have an oil cooler installed. The hard lines are run to the front inside the rocker as stock on a '69 S. The cooler was removed prior to engine rebuild due to leak. I want to install a new cooler, but am worried about using the old lines. If there is any trash in the old lines, it would seem to be too risky. Is there a way to flush out the old lines? How about using an in-line or auxiliary oil filter? Which oil cooler should I go with?

Any information or help on these issues is greatly appreciated!

[Tspringer]

punt