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The 289-2v was built by a very reputable local engine builder. It was broken in on his dyno and all numbers looked exactly correct. It put out 200.5 HP at 4400 RPM.

Here is the problem/question. It is now in the car and has only about 200 road miles on it.

Today I was coming back from near the Mexican border and the oil pressure was about 1/2 scale, at 70 MPH, (3,000 RPM) the pressure suddenly dropped to the low end. When I slowed down, expecting to have to pull off the freeway, the oil pressure went back up to 1/2 scale. I drove on to the office at about 55 and the OP stayed at 1/2 or above.

Checked the oil level. Slightly above the full mark. Clean and clear. Started up and then drove home where speeds did not exceec 50 MPH. Oil pressure went to about 3/4 scale then settled back to 1/2.

What the heck is going on here. Why would the pressure go down at 70 MPH and then come up at slower speeds? Bad oil pump? Bad pressure sender? Bad original gauge? The Fuel and Temperature gauges were stable and accurate, so I don't think the CV regulator is bad.

Any ideas or theories appreciated. I have a straight mechanical gauge that I can install which might help solve the mystery.
 
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My first reaction is to make sure that the oil pressure sending unit is properly hooked up -- it's easy to check and since you must have recently disconnected and reconnected it, a possible source for such odd readings.
 

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No mystery...dollars to donuts it's in the guaging system...loose wire/connection or bad sending unit...my bet's on wiring..

You know why pilots sometimes ignore the fire warning light in the ****pit?? *G*

If you're concerned, plumb a temp mech guage and run the boots off it...
 
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