oil light flickering at high rpm

BTW, I found the 2 prong switch that the OP has pictured; it is under the gauge sender in the pix. It is 2 lb switch from a Walters marine engine. The standard Mopar ones light at below 8-10 lbs. BTW, the response time of a gauge can vary; lights usually are very fast. So I would not ignore what the light is telling me.

If this switch is going off and is accurate, it says you have < 2lbs of pressure at that point in the engine. I have to wonder if the prior owner had a lot of light flickering with the 8 lb Mopar switch and put this 2 lb switch to reduce the number of times the light flickered! So be careful when you put in the lighter weight oil and look at the pressure immediately. The P.O. might have experienced an oil pressure problem and masked it with the heavy oil, either out of ignorance or on purpose.

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