Try installing a short brass 1/8" NPT pipe nipple and a 45 degree elbow beside the distributor (with the distributor removed) to make the port easier to reach. I do that on a lot of the small block engines I build when I use a mechanical oil pressure gauge. The port down beside the oil filter doesn't give an accurate pressure reading for some reason on a lot of engines. I learned that on a dyno run about 20 years ago.
Jerry

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